Combat

Niche is a turn-based system meaning that during combat players and the creatures they fight against each are given a turn to perform a number of actions before moving to the next creature's turn.

At a high level combat follows the following flow:


 * 1) Once combat has begun all creatures must first roll their initiative.
 * 2) Determine if any creatures would be unaware and therefore surprised.
 * 3) Creatures go in sequence of highest to lowest initiative.
 * 4) After all creatures have taken their action a new round occurs starting again at the top of the list.
 * 5) Repeat 3 and 4 until combat has ended.

Initiative and Combat
At the start of combat, each creature must make an initiative check. An initiative check is 1d20 + the creature's initiative modifier. A creature's initiative modifier is their Dexterity modified plus any other bonuses they have to initiative such as from feats, items, or other sources. In combat characters act in order, counting down from the highest resulting check to the lowest, before starting a new round and beginning again from the top. Characters follow this same order until the end of combat, though some actions may allow a character to change their place in the initiative.

If two or more creatures have the same initiative check result, the tie is determined by the highest initiative modifier used in the check. If a tie still exists, then tied characters should roll to determine who goes before the other; continue rolling as additional ties occur. This tiebreaker roll does not replace the initial initiative roll.

If an ability would add from, subtract from, or replace the initiative check the creature rolled after the results and turn order have been determined you may adjust the initiative check and re-determine the character’s position in the initiative turn order, handling any ties as stated above as normal.

Even if you can’t take actions, you retain your initiative score for the duration of the encounter.

A Round of Combat:
A single combat round represents 6 seconds in the world; making 10 rounds equal a minute of combat. This value is not adjusted if there are less or more creatures in combat at the same time, as it is assumed most actions within a round are happening at the same time or within rapid sequence of each other.

Each round begins with the character with the highest initiative then proceeds in order from highest to lowest initiative. When a characters turn is up in the initiative sequence, the character may perform their round worth of actions. A character cannot take an action outside of their turn outside of Immediate Actions, Reactions, and Readied actions.

When an effect lasts for a number of rounds the effect starts on the initiative it began on, and ends just before the same initiative count that they began on.

Surprise Rounds
When combat starts, if a creature is not aware of their opponents but they are aware of you, the creature is surprised.

How to Determine Awareness
Generally awareness is determined if a creature was unseen, stealthed, or otherwise not successfully spotted by a perception check. Awareness is not limited to a single side of a combat, and some combatants may be aware, all may be aware, none, even with some on each side unaware. Usually if a creature is hidden or is actively attempting to hide a perception check is needed to determine awareness. If no one or everyone is surprised, no surprise round occurs.

The Surprise Round
If some, but not all, of the creatures in a combat are aware of their opponents, then a surprise round occurs. A surprise round is similar to a normal round of combat, following initiative sequence as normal. Creatures who started the battle aware of their opponents may take a single standard or move action during their surprise round. Creatures may also take free, swift, or immediate actions. Initiative order is followed as normal during a surprise round, simply skipping over the turns of creatures who were unaware during the surprise round.

Flat-Footed
One combat has begun all creatures are treated as flat-footed until they have had a chance to act. Once a creature takes their first turn in combat they are no longer flat-footed for the remainder of combat; some abilities may allow a creature to be treated as flat-footed after this, with the ability specifying the duration of this effect.

When a creature is flat-footed they cannot use their dexterity bonus or any dodge bonuses they have to AC. Some abilities and class features may allow a creature to avoid being flat footed at the start of combat. In addition, a flat-footed character can’t use reactions.

Action in Combat
During a turn of combat a character can perform various actions, each to help categorize the time and effort it takes to perform within a single character’s turn, usually within the timeframe of a single 6-second combat round.

There are seven types of actions that we will cover, and how each can be used within combat.


 * 1) Standard
 * 2) Move
 * 3) Full-round
 * 4) Swift
 * 5) Immediate
 * 6) Reaction
 * 7) Free

During a creature’s turn they receive a Standard, Move, and Swift action to perform various actions with. Some actions such as reactions and immediate actions can be performed outside of a creature’s turn. Actions such as full-round actions require a creature to exchange their standard and move action to perform. Below we shall detail each action and basic actions that can be taken with each.

Standard Action
Standard action is the most common form of action in the system; commonly used to make an attack or cast a spell. If an ability does not specify its own action, or another action it is made part of, it is assumed the action to be by default be a standard action.

Attack Action
An attack action is a type of standard action a character can use to make a single attack with a weapon. Some options modify this type of action such as the vital strike feat. When taking an attack action you can apply a number of feats and abilities that modify an attack action (such as the heavy blow feat and vital strike feat being applied to the same attack action made with an unarmed strike). You may apply these to other options that can take the place of an attack action (such as some combat maneuvers), though options that do not deal damage (such as a trip combat maneuver) might gain no benefit from being combined with other attack action options (such as vital strike as there is no damage to improve).

Some abilities in combat such as class features are standard actions that may allow for an attack, but in themselves are not an attack action and cannot be combined with other standard actions that are also attack actions. Abilities that trigger an extra attack in addition to an attack action are not attack actions in themselves unless specified otherwise.

Some actions may count as an attack action, but have their own action. As such Whirlwind Strike is valid to stack both vital strike and cleave through with; but Great Cleave would be invalid for combination as both it and Whirlwind Strike both require their own Full-Round actions to begin using. Charge is another example where it is its own full-round action that ends with an attack action, making it invalid to combine with whirlwind strike or great cleave, though cleave through and vital strike are valid.

Focused Attack Action: A focused attack action is an attack action in almost every way except that it cannot be used with other focused attack actions. This limiter is in place to ensure certain options may still be combinable with attack actions but cannot be combined with other powerful options (such as Iaijutsu Focus and Double slike being both focused attack actions and as a result unable to be combined together.

Aid Another
When in melee combat you can attempt to help an ally attack or defend. If the creature engaged with your ally is within your threatened area you can attempt to aid your ally as a standard action. You make an attack roll, if the result is greater than 10 you succeed and grant your ally a +2 bonus on their next attack roll against the target, or a +2 bonus against the foe’s next attack. Multiple characters can aid the same ally and the bonus may stack.

Aid another may also be used to assist with skill checks, but rather than an attack roll, you instead make a skill check against DC 10, if successful you grant a +2 bonus to their skill check. Some activities, such as picking a lock, may have limitations to how many creature can assist at the same time.

Ready An Action
Readying an action is a standard action, allowing you to prepare to take an action later. You may ready a single standard, move, swift, or free action as part of this standard action.

Readying an action allows you to specify a condition for the action to occur; once the condition has been met the readied action is triggered and the action that was readied occurs. This does not adjust your place in the initiative, but this allows your action to take place before the triggering condition occurs. You can take a 5-foot step as part of your readied action, but only if you don’t otherwise move any distance before the readied action occurs.

Example
For example a creature may attempt to distract a spellcaster with an readied action, such as with the trigger of “if they start casting a spell”. When the designated creature would being to cast the readied action would occur just as the cast would benign allowing the readied action to attack to occur. A successful hit would force the spellcaster to make a concentration check to avoid losing the spell, and if fails would lose the spell rather than successfully casting the spell.

Feint
To perform a feint you must make a bluff check as a standard action. The target makes an opposed sense motive check. If successful the target is denied their dexterity bonus against the next melee attack you make. Feinting against a non-humanoid creature imparts a -4 penalty to the bluff check, while a feint against a target with an intelligence of 1 or 2 imparts a -8 penalty to the bluff check.

Use a Skill
Most skills are standard actions to use, but some might be move actions, full-round actions, free actions, or have durations measured in minutes to use. The individual skills will define the action required to perform skills.

Total Defense
As a standard action a creature may raise their guard in preparation for incoming attacks. A creature that takes a full defense gains a +4 dodge bonus to their AC for 1 round. A creature does not threaten nearby squares while taking a full defense, nor can they use reactions, except for the Raise Shield reaction if you are wielding a shield while taking the total defense.

A creature may choose to take a Total Defense as a full-round action. This functions as a normal total defense except granting a +6 dodge bonus instead of +4, and also granting a +2 dodge bonus to reflex saves.

Cast a Spell
Most spells require 1 standard action to cast, with some exceptions lowering a spell to a swift or raising it to a full-round action to cast.

Move Action
A move action is an action used for movement or actions that take a similar amount of time, usually representative of an effort less than a standard action but more than a swift action.

You may take any move action in place of a standard action, allowing a creature to make two move actions within the same turn. As long as a creature does not move any distance (squares) in a round you can take a 5-foot step.

You can take a move action in place of a standard action. If you move no actual distance in a round (commonly because you have swapped your move action for one or more equivalent actions), you can take one 5-foot step either before, during, or after the action.

Move Your Speed
The most common use of a move action is for a creature to move up to their speed. A creature’s speed is usually determined by their race or creature type, usually 30 feet. Each square of movement is treated as 5 feet as such a creature could use a move action to move anywhere between 1 to 6 squares as a move action.

Movement made as part of climbing or swimming is either made at a quarter of one’s land speed or using the creature’s climb or swim speed if they possess one. Flying may only occur if the creature possesses or is granted a fly speed. Each of these special forms of movement may require swim checks.

Mount or Dismount
Mounting or dismounting requires a move action.

Crawling
While prone a creature may still attempt to move by crawling, though doing so is considerably slower than normal movement. As a move action a creature may crawl at a maximum of a 1/4th of their total move speed (minimum 5 feet). This movement provokes attacks of opportunity as normal.

Stand-Up
While prone a creature may attempt to stand up again, though doing so provokes attacks of opportunity.

Draw or Sheathe a Weapon or Item
Drawing a weapon or Item is usually a move action. Objects retrieved in this way must be easily accessible such as a sheath, bandolier, holster, belt pouch, or similar sort of container. Objects stowed in a backpack require more effort to retrieve and cannot be retrieved with just a move action and may take a full-round action to retrieve as the creature searches for the item in the larger container; while ammunition such as arrows, bolts, or bullets are drawn as a free action as part of the act of reloading.

Stowing a weapon or item is similar to drawing one and requires a move action, though an item may be stowed in a larger container such as a backpack as a move action as it is easier to stow an item than retrieve from such containers.

Creatures with a base attack bonus of +1 or higher may draw up to two weapons, if they have a free hand to hold each, as a part of moving. This cannot be used as part of a 5-foot step.

If you have a base attack bonus of +1 or higher, you may draw a weapon as a free action combined with a regular move. If you have the Two-Weapon Fighting feat, you can draw two light or one-handed weapons in the time it would normally take you to draw one.

Drawing ammunition for use with a ranged weapon (such as arrows, bolts, sling bullets, or shuriken) is a free action.

Full-Round Action
A full-round action consumes all of a character’s effort during a round. A creature must be able to take a single standard and move action within a round to perform a full-round, effectively trading their standard and move for the full-round action.

A creature may still take a 5-foot step before, during, or after the action though full-round actions do not allow you to take a 5-foot step.. You can also perform free, swift, immediate, and reactions as normal.

Full Attack Action
If a creature can make more than one attack per round, such as through enough base attack bonus, fighting with two weapons, or some other reason, you must use a full-round action to make the additional attacks. Targets of the attacks do not need to be specified ahead of time and may be determined as each attack is made. A creature may take a 5-foot step as normal and may do so between attacks.

Attacks made from high base attack bonus must be made from highest to lowest bonus. When fighting with a main and off-hand weapon a creature may strike with either first, but must choose which is considered the main hand and off-hand for that full-attack before any attack rolls are made.

Coup de Grace
As a full-round action a creature may use a melee weapon to deliver a coup de grace to a helpless target. Ranged weapons may also be used but require the creature to be adjacent to their target. Performing a coup de grace provokes attacks of opportunity.

A coup de grace is treated as if the attack automatically hit and scored a critical hit. If the target survives the damage from this attack they then must make a fortitude save against 10 + the damage dealt. If the target fails this fortitude save they immediately die. A coup de grace is ineffective against creatures immune to critical hits, dealing no critical damage and does not require the creature to make a fortitude save.

Move 5 Feet
In some situations your movement may be reduced to the point you do not have sufficient speed to move a single square; this can be through effects reducing your speed, or difficult terrain making the movement too great to move. When in these situations a creature can instead spend a full-round action to move 5 feet in any direction. Unlike a 5-foot step this movement provokes attacks of opportunity as normal.

Run
As a full-round action a creature can choose to run, rather than moving twice a character may move up to four times their speed in a straight time, or three times your speed if in heavy armor). A creature who performs a run action loses their dexterity bonus to AC until the start of their next turn.

A creature can continuously run for a number of rounds equal to 10 + their constitution score. Once a creature has gone beyond this limit they must make a DC 10 Survival check to continue running. This check must be repeated each round you continue to run, increasing the DC by 2 for each check you have made previously, and upon a failed check the creature must stop running. If a creature stops running before failing a check, but begins to run again the DC continues from the last highest value they had checked against. If a creature takes a short rest they may begin running as normal without needing to make survival checks.

Withdraw
A creature may choose to withdraw from a dangerous situation as a full-round action. When taking a withdraw action you move up to double your speed. The square you first move from is not considered threatened by any opponent you can see; this means targets that you cannot see, such as invisible creatures, may threaten you as normal. If blinded you cannot withdraw unless you have some other sense such as blindsight to allow you to see creatures clearly. All squares after the first you move from are considered threatened as normal.

You cannot withdraw using a form of movement you do not possess a speed for; for example a creature cannot withdraw via swimming unless they possess a swim speed.

Restricted Withdraw
If you are unable to make a full-round action, and can only take a standard action, such as through a status ailment preventing you from taking a full turn worth of actions, you may instead make a withdraw as a standard action, but may only move up to your speed rather than double your speed.

Charge
As a full-round action a creature may perform a charge, allowing you to move up to double your speed and make a single attack at the end of the charge. Before performing a charge the charger must designate their target of their charge and have line of sight of this target.

When making a charge the creature must be able to move at least 10 feet (2 squares) to your designated opponent. The charger must have a clear path to their target with nothing that hinders their movement, such as difficult terrain or other obstacles. The charger must move to the closest space from which they can attack the opponent from, and as such this square cannot be occupied or blocked in any way. The charger’s path must not pass through any creature, including allied creatures, though helpless creatures do not hinder the charge. Movement taken during the charge provokes attacks of opportunity as normal.

At the end of the charge the creature may take a single melee attack action with a +2 bonus on the attack roll. After performing the charge the charger takes a -2 penalty to their AC until the start of their next turn.

Restricted Charge
If you are unable to make a full-round action, and can only take a standard action, such as through a status ailment preventing you from taking a full turn worth of actions, you may instead make a charge as a standard action, but may only move up to your speed rather than double your speed.

Special Charges
Sometimes a creature may be able to perform a charge via swinging, falling, or some situation where a creature can rush towards a creature and perform an attack but not through their own movement. As the creature is not moving through their own movement, but rather through momentum of a swing or fall, the creature must instead move at least 20 feet and start on a higher elevation than their target to perform this action. This action otherwise behaves as normal for a charge.

Free Action
Free actions represent actions that take such a small amount of time or effort to perform they do not interfere with other actions being taken. You can perform more than one free action in a single turn, though there may be limits on what is considered a reasonable number of free actions within the same turn, decided by the GM.

Drop an item
You may drop an item you are currently holding as a free action. You may drop the item in your own square or an adjacent square.

Drop Prone
A creature may choose to drop prone within their space as a free action.

Non-Actions
Some actions are minor and are not even considered free actions. These actions do not take any amount of time at all and are considered an inherent part of doing something else.

Swift Action
Swift actions consume a small amount of time that are quick but expend more effort than a free action, and as such a creature is limited to a single swift action.

Immediate Action
An immediate action is very similar to a swift action, but can be performed at any time, even if it’s not your turn. Using an immediate action on your own turn is the same as using a swift action and as such uses up your swift action for that turn. If you use an immediate action when it is not your turn, it instead uses your swift action for your upcoming turn; losing the ability to make a swift action on your next turn. A creature cannot use an immediate action while they are flat-footed.

Reactions
A creation is a type of action that may be taken outside their normal turn of actions, similar to an immediate action, but rather than taking up another action, a creature is allotted a number of reactions per round. A creature has a number of reactions per round equal to their wisdom modifier (minimum 1) and gains an additional reaction per 5 hit dice the creature possesses, though some abilities may allow a creature to have more reactions per round than normal.

As the name suggests reactions normally require specific circumstances to be used in reaction to another event or action being taken.

While some abilities or feats may grant additional uses for a creature’s reactions, there are a number of default options a creature may use as a reaction.

Drop Prone
When targeted by an attack roll a creature may choose to drop prone as a reaction. This happens when the attack is declared but before the attack roll has been made, as such applying the appropriate modifiers for being prone.

Attacks of Opportunity
When a combatant in melee is distracted or lets their guard down through taking a reckless action a nearby combatant may take advantage of this to attack them as a reaction. These are known as attacks of opportunity.

Attacks of opportunity may be made when a creature performs an action that would provoke an attack of opportunity, such as moving away or casting a spell, while within the threatened area of a creature.

Threatened Squares
A creature’s threatened area is any space within their reach that they could make a melee attack. For most medium sized creatures, this means all adjacent squares to their space.

Certain abilities, or simply being a creature of larger size may grant a greater area of reach and therefore a greater threatened area.

Provoking an Attack of Opportunity
Moving out of a threatened square usually provokes attacks of opportunity from threatening opponents. There are two common methods of avoiding such an attack—the 5-foot step and the withdraw action.

Some actions, when performed in a threatened square, provoke attacks of opportunity as you divert your attention from the battle. Many actions do not provoke an attack of opportunity unless stated otherwise.Some actions that normally provoke attacks of opportunity may have exceptions to this rule.

Making an Attack of Opportunity
An attack of opportunity is a single melee attack, and uses up one of a creature’s reactions for the round to perform. You don’t have to make an attack of opportunity if you don’t want to. You make your attack of opportunity at your normal attack bonus, even if you’ve already attacked in the round.

An attack of opportunity is immediately resolved before the action that provoked it, then the creature’s action resolves. Initiative is not changed and the flow of combat continues as normal. Unless stated otherwise an attack of opportunity normally does not interrupt the action that provoked it unless the creature would be no longer capable of performing it (such as being unconscious due to hit point damage).

Restricted Activity
In some situations, you may be unable to take a full round’s worth of actions. In such cases, you are restricted to taking only a single standard action or a single move action. Unless otherwise specified a character always retains their ability to use swift, immediate, and free actions when their actions are limited to a single standard ore move.

Delay Turn
At the start of a creature’s turn, before they have taken an action; they may choose to delay their turn. When a creature delays their turn, you may select a different place in the initiative later in the combat; this may be later in the same round or some point during the next round. Once your new position is selected, adjust your initiative check to be 1 lower than the character who is before you in your new position, keeping yourself above any other characters in the initiative should your new check be tied with theirs.

A character does not get back the turn they gave up to delay, and unlike a readied action cannot delay to interrupt an upcoming action.

Take 5-Foot Step
You can move 5 feet in any round when you don’t perform any other kind of movement. Taking this 5-foot step never provokes an attack of opportunity. You can’t take more than one 5-foot step in a round, and you can’t take a 5-foot step in the same round that you move any distance.

You can take a 5-foot step before, during, or after your other actions in the round.

You can only take a 5-foot-step if your movement isn’t hampered by difficult terrain or darkness. Any creature with a speed of 5 feet or less can’t take a 5-foot step, since moving even 5 feet requires a move action for such a slow creature.

You may not take a 5-foot step using a form of movement for which you do not have a listed speed.

Fighting Defensively
A player can choose to fight defensively; If you do so you take a -4 on all attacks in a round to gain a +3 dodge bonus to AC. You must choose to be fighting defensively before making an attack roll on your turn, and its effects last until your next turn.

At +8 base attack bonus and every 8 thereafter you may take an additional -1 penalty to attack rolls and gain a +1 dodge bonus to defense. You may choose to incur some, all, or none of this increased penalty, but do not gain the corresponding bonus for any penalty not gained (As such a 16 BAB character may choose to take a --5 penalty rather than -6, but would only gain a +4 dodge bonus instead of +5)

Types of Abilities
Special abilities and class features usually have an associated type between Supernatural or Extraordinary. These determine any potential restrictions such as anti-magic affecting them or not.

Supernatural Abilities (Su)
Supernatural abilities are abilities that are magical or pull from an outside force. While these abilities do not require concentration to use they do not function within areas where magic is suppressed or negated, but are not subject to spell resistance.

Extraordinary Abilities (Ex)
Extraordinary abilities are non-magical in nature, but allow a creature to perform great feats within or beyond the limits of the mundane. These abilities usually do not require concentration nor are they affected by anything that would suppress or negate magical effects.

Degrees of Success and Failure
Also mentioned within the magic rules page, this system utilizes degrees of success and degrees of failure as a general term to describe a threshold of additional success or failure an action might provide. As many actions in this system use opposed rolls the margin in which an action may succeed can be highly variable and subject to the result of the dice; as such many abilities have additional or lessened effects based on degrees of success and failure.

A degree of success or value is an increment of 5 above or below the target value.

For example a Reflex save attack rolls a 10 total value, while the saving throw of their opponent was a 15. In this case the resulting attack would result in a degree of failure, while had they roll a 11 would have simply failed, but not a degree of failure. Alternatively had the attacker rolled a 15 and the defender rolled 10 they would have had a degree of success. Many save attack based abilities may have a lessened effect as long as they fail by one degree, while some may have additional or more punishing effects from additional degrees of success.

Attacks
Normally attacks are made as part of an attack action, or full attack action, but many other abilities or actions may call for an attack, and as such are not detailed under a specific action type.

Melee Attacks
With a normal melee weapon, you can strike any opponent within your reach, which for most medium sized creatures is 5 feet, which is any square adjacent to the creature’s space. Some melee weapons may have the reach feature adjusting the creature’s reach while wielding that weapon; see the reach weapon feature on the weapon’s page for more information on the reach property.

Some creatures may have spells, abilities, or features that increase their natural reach beyond 5 feet. These creatures may attack up to their granted reach and any weapons wielded by the limb or similar feature that grants them this increased natural reach may also attack within this natural reach.

Unarmed Attacks
Creatures may choose to make attacks without a weapon, but rather with punches, kicks, or headbutts. When doing so this is called an unarmed strike, which has the following properties:

Unarmed Strike: An unarmed strike is treated as a light martial weapon with the monistic keyword. An unarmed strike deals 1d4 bludgeoning damage for a medium creature (1d3 if small, 1d6 if large). An unarmed strike can normally only deal nonlethal damage, though a creature may choose to take a -4 penalty to their attack rolls with an unarmed strike to deal lethal damage. A creature without martial weapon proficiency is not proficient with unarmed strikes and takes the normal penalties for attacking without proficiency. Some feats or equipment may allow a creature to deal lethal damage or grant proficiency with an unarmed strike.

Enhancing Unarmed Strikes: As unarmed strikes are made with a specific limb, items such as enhanced gauntlets would only enhance your punches, but not any headbutts or kicks. Some spells or abilities may enhance a creature rather than a specific limb to apply to any unarmed strike.

Using Gauntlets: A gauntlet is a way for a player to use an unarmed strike without martial weapon proficiency; a gauntlet is a simple weapon that deals unarmed strike damage, is treated as an unarmed strike, but allows a player to deal lethal damage as well as not provoke as long as they’re proficient with the gauntlet. This does not count as actual proficiency in unarmed strikes; thus they would not quality for feats such as improved unarmed strike; but it allows a player to start their journey using unarmed strikes if they lack the proficiencies to do so.

Melee Touch Attacks
A melee touch attack is made like a normal attack, and as such can be made as an attack action or part of a full attack action; in addition a creature can substitute any melee attack for a touch attack. Unlike a normal attack a melee touch attack is made against a creature’s touch AC check rather than normal AC, as it is simply your ability to make contact with the creature rather than the force needed to break through their defenses.

By itself a melee touch attack does nothing, no damage roll is made on success, nor does any other effect occur. Some abilities or spells may call for a melee touch attack, in which situation the melee touch attack is a conduit making a successful touch attack impart the effects of the spell or ability to the target creature.

Feats, abilities, or effects that affect an unarmed strike also apply to a melee touch attack, though unlike unarmed strikes a creature is automatically proficient in melee touch attacks.

Ranged Attacks
With a ranged weapon, you can shoot or throw at any target that is within the weapon’s maximum range and in line of sight. The maximum range for a thrown weapon is five range increments. For projectile weapons, it is 10 range increments. Some ranged weapons may have different maximum ranges, as specified in their descriptions.

Shooting or Throwing into a Melee
Making an attack with a ranged weapon against a target engaged in melee grants a penalty to attack rolls due to the chaotic movement in melee combat. If the target of the attack threatens an ally’s square or is in the threatened area of another creature they are considered in melee and grant a -4 penalty to attack roll. A creature that is unconscious or immobilized  is not considered engaged in melee unless they are being attacked. In addition if you are within the threatened area of a creature you take a -4 penalty to attack rolls against that creature.

For each size category your target is then the largest creature it is engaged in melee combat with, this penalty is reduced by 1 (minimum 0). In addition if a creature is at least 10 feet away from the target, but is still threatened, this penalty is reduced by 2 plus an additional 1 for every 5 feet beyond (minimum 0).

Ranged Touch Attacks
Ranged touch attacks are similar to ranged attacks except they target a creature’s touch AC check rather than normal AC. Unlike a melee touch attack, ranged touch attacks usually cannot be made freely unless a spell or ability calls for a ranged touch attack. Some weapons or objects may call for a ranged touch attack when thrown and as such can be used as normal for a thrown weapon; such as slash weapons.

Throwing A Splash Weapon
A splash weapon is similar to a thrown weapon, but designed to break or explode on impact affecting not only the target, but other nearby creatures. Attacks with slash weapons are made as ranged touch attack against their target. Splash weapons are treated as simple weapons for the purposes of determining proficiency.

Many splash weapons will specify their damage on a direct hit, or a splash hit. Direct hit damage occurs when your ranged touch attack successfully hits its intended target, dealing the listed direct hit damage. In addition all creatures within the listed area of the splash weapon take the listed splash damage. Splash weapons cannot deal precision damage, even if they have a successful direct hit. A creature throwing a splash weapon can always choose to hit a grid intersection or square, requiring simply a ranged attack against AC 5. If targeting an intersection occupied by a creature in this way, the attack cannot result in a direct hit on the occupying creature and will only deal splash damage.

If the creature misses the target or grid intersection with the splash weapon attack, roll a d8. Starting from 1 which is the square adjacent to the target and closest to the thrower go clockwise around the target square counting from 2 to 8, using this to determine which square is hit from the d8’s resulting roll. Once it is determined where the weapon lands, it will deal splash damage to all creatures in that square and in adjacent squares. A missed attack that lands in a different creature’s square than the intended target is not treated as a direct hit.

When targeting a creature that is larger than medium you may pick any square the creature occupies using that square as the target location should it miss and need to determine where it lands; a miss that lands within the creature’s square does not turn a miss into a direct hit, though will deal splash damage as normal.

Unless otherwise specified, splash weapons may be thrown as any other thrown weapon, but do not treat their damage as weapon damage for the purposes of effects that multiply or add additional weapon damage. Splash weapons do not deal strength modifier damage when thrown like normal splash, and are destroyed after their effect resolves making them unrecoverable.

Natural Attacks
Claws, bites, tail slaps, or other such items a creature may possess are referred to as Natural Weapons. Natural weapons are used as light melee weapons that the creature is automatically proficient with. The damage of each natural weapon usually depends on its type and is noted for the specific creature’s entry or ability that grants it. You do not receive additional attacks for possessing multiple natural weapons, but may utilize them as main hand and off-hand weapons for the purposes of two-weapon fighting.

Natural weapons occupy a specific limb, and as such if two natural weapons occupy the same limb they cannot be treated as attacks with different limbs. For example a character using two weapon fighting could not use the bite as a main hand and the gore as an off hand, but could alternate between bite and gore attacks as main hand attacks while making off hand attacks with a claw. If a natural weapon specifies “other” this usually means it is its own limb in itself and therefore doesn’t share a limb (such as wing attacks). Natural weapons which occupy the hand slot usually come in pairs and as such can be used in main and off hand attacks as long as it is a different hand utilized for each. Some natural weapons as detailed as “other” and as such usually are within themselves a limb and do not share a limb with other natural weapons.

Natural weapons come in various shapes and sizes. Generally unless specified otherwise a natural weapon has the following statistics:

Combat Statistics
This section details the dice rolls and statistics that determine success in combat.

Attack Roll
An attack roll represents a creature’s attempt to strike another creature, when making an attack roll a creature rolls a d20 and adds their attack bonus. If your result equals or beats the target’s Armor Check, you hit and deal damage.

Attack Bonus
Your attack bonus with a melee weapon is:

Base attack bonus + Strength modifier + size modifier

Your attack bonus with a ranged weapon is:

Base attack bonus + Dexterity modifier + size modifier + range penalty

Other miscellaneous modifiers exist that may add or subtract from this value in the final attack roll; in addition some abilities, such as the weapon finesse minor perk, may change the ability score modifier used in these calculations.

Base Attack Bonus
Base attack bonus is derived from a character’s class level of a creature’s type and hit dice (or sometimes the combination of both). Base attack bonus increases at different rates depending on their class, sometimes referred to as 1/2, 3/4, and full progression. Base attack bonuses gained from different sources, such as when a character is a multiclass character, stack. An additional attack is gained when a base attack bonus reaches +6  and every 5 base attack bonus base attack bonus thereafter, details on these additional attacks are detailed on the “full attack action”.

BAB and Multiclassing
Normally a character can simply follow the chart on their class to determine their base attack bonus, but when multiclassing you need to add the base attack bonus progressions from the levels in each class to determine the total base attack bonus. When adding together full BAB classes the math is simple, but when adding ½ and ¾  your BAB is calculated to the decimal point before being added together and then rounded down. This system is so non-full base attack bonus classes do not hinder their progression by taking levels in other non-full base attack bonus classes.

For example, without fractional bonuses should a level 1 wizard multiclass into level 1 priest their BAB would remain a +0 despite being level 2. With fractional bonuses their BAB is in reality 0.5 meaning added together their BAB becomes 1. This otherwise would have no benefit should a level 1 wizard multiclass into level 1 fighter, their BAB would be 1.5, which would mean it is still only +1.

A ½ BAB class is a class that gains 0.5 BAB each level to +10 at 20th level.

A ¾ BAB class is a class that gains 0.75 BAB each level to +15 at 20th level.

A full BAB class is a class that gains 1 BAB each level to +20 at 20th level.

Critical Hits
When a d20 rolls a 20 (before modifiers) this is known as a natural 20. When scoring a natural 20 for an attack roll this is considered a critical threat. A critical threat always is considered a hit, but requires an additional roll to confirm if the hit is also a critical hit. When confirming a critical threat simply roll another d20 plus all the modifiers from the original attack roll that made the critical threat; if this attack would also succeed to hit the hit becomes a critical hit. When confirming a critical hit the opponent does not roll another armor check and instead compare the confirmation roll against the original roll the threat was made against. The critical confirmation roll does not need to be a natural 20 to confirm, but an additional natural 20 will automatically confirm the crit. If the confirmation roll would fail to overcome the opponent’s AC roll the hit remains a regular hit.

Critical Multipliers
When a critical hit has been successfully made usually this means additional damage. Critical damage is determined by the critical multiplier to indicate how many times you will roll to calculate damage; for example a multiplier of x2 would roll damage and add all its usual modifiers and bonuses to damage twice. Bonus damage such as precision damage, and extra dice from weapon special abilities (such as elemental fury) are never multiplied by a crit; some other effects may indicate if or if not they are multiplied on a critical hit. Unless otherwise specified the critical multiplier for an attack is x2; many weapons may have higher critical multipliers.

Some weapons deal more damage on a critical hit than others.

For example:

A weapon with a 20 / x2: The weapon deals double damage on a critical hit, while a weapon with a 20 / x3: The weapon deals triple damage on a critical hit, and a weapon with a multiplier 20 / x4: The weapon deals quadruple damage on a critical hit. In this format the 20 indicates the threat range while the x2, x3, and x4 indicate the weapons critical multiplier.

Critical Threat Range
Some weapons may have a critical threat range beyond 20, allowing for a critical threat on a dice roll below 20. Any dice roll below 20 is not considered an automatic hit, and as such must still overcome the opponent’s armor check roll to be considered a hit and a critical threat even with the increased threat range.

Examples:

A weapon with a 19–20/×2 threat range would score a threat on a natural roll of 19 or 20 (instead of just 20) and would deal double damage on a critical hit. A weapon with a 18–20/×2 threat range would score a threat on a natural roll of 18, 19, or 20 (instead of just 20) and deals double damage on a critical hit.

Spells and Critical Hits
Any spell that requires an attack roll can critically hit if they also would deal damage on a successful hit, dealing the standard x2 damage on a confirmed critical. Save attack rolls cannot critically hit but may still be automatic successes on a natural 20.

Stamina
Stamina is a pool that all martial classes have access to. Most stamina pools are Constitution modifiers plus their levels in martial classes. All classes have a type such as martial, hybrid, or magic, allowing a player to quickly identify what is a martial class to be counted for this progression. When multiclassing the initial Constitution bonus is not added more than once, and if a class allows for a different ability modifier than Constitution you use the higher of the two stats to determine the total stamina pool (such as a class allowing Wisdom for Stamina mixed with a class that uses the normal constitution would use Wisdom if it was higher than their Constitution, and would not add both their Constitution and Wisdom for uses per day).

Short rest
You must rest for 5 minutes; you do not need to sleep, but you can’t exert yourself (for example run, perform non-mental skill check, or enter another combat in this time). If performing a task during a short rest (such as applying an armor repair kit during a short rest) you cannot perform additional tasks such as these during this short rest, and must take an additional short rest to perform these additional tasks.

Martial Prowess Bonus (MPB)
Martial Prowess Bonus is the count of all levels in classes with the stamina class feature. Classes with the stamina feature are considered martial classes. This value is generally used to help determine things such as the scaling of saves for certain effects.

Armor Check:
Your Armor Check (AC) represents how hard it is for opponents to land a solid, damaging blow on you. When being attacked both the attacker’s attack roll result is compared against the defender’s AC result.. Similar to an attack roll a Armor Check is made by rolling a d20 and adding their AC bonus.

If the attacker rolls higher the attack is a success, if the defender rolls higher then the attack is a miss.

AC Bonus
Your AC (Armor Check) bonus is equal to the following:

Base Defense Bonus + armor bonus + shield bonus + Dexterity modifier + other modifiers

Note that armor limits your Dexterity bonus, so if you’re wearing armor, you might not be able to apply your whole Dexterity bonus to your AC (see Table: Armor and Shields).

Sometimes you can’t use your Dexterity bonus (if you have one). If you can’t react to a blow, you can’t use your Dexterity bonus to AC. If you don’t have a Dexterity bonus, your AC does not change.

Other Modifiers
Many other bonuses can modify a creature’s AC, below are some examples:


 * Enhancement Bonuses: Enhancement bonuses usually are not applied directly to AC, but rather are applied to one’s armor, natural armor, or shield to increase the bonus it provides.
 * Deflection Bonus: Magical deflection effects ward off attacks and improve your AC.
 * Natural Armor: If your race has a tough hide, scales, or thick skin you receive a bonus to your AC.
 * Dodge Bonuses: Dodge bonuses represent actively avoiding blows. Any situation that denies you your Dexterity bonus also denies you dodge bonuses. (Wearing armor, however, does not limit these bonuses the way it limits a Dexterity bonus to AC.) Unlike most sorts of bonuses, dodge bonuses stack with each other.
 * Size Modifier: You receive a bonus or penalty to your AC based on your size.

Touch Attacks
Some attacks may bypass armor, including shields and natural armor. The attacker need only touch a foe for such attacks to take full effect. The attacker makes a touch attack, which may be a melee or ranged touch attack based on the effect calling for the touch attack.

When targeted by a touch attack your AC does not include any armor bonuses, shield bonuses, or natural armor bonuses (including any enhancement bonuses to these individual bonuses). This is normally tracked as a creature’s Touch AC Bonus for ease of calculation. All other modifiers, such as size, dodge bonuses, and other bonuses normally applied to an AC Bonus are still applied.

Base Defense Bonus(BDB)
While leveling your AC will gain a passive bonus determined by your class’s BAB.

A base defense bonus is an AC bonus derived from character class and level or creature type and Hit Dice (or combination’s thereof). Base defense bonuses increase at different rates for different character classes and creature types. Base defense bonuses gained from different sources, such as when a character is a multiclass character, stack. This bonus to AC is a dodge bonus. Normally a base defense bonus is calculated at ½ of a character’s base attack bonus, but some feats and abilities may boost a character’s base defense bonus progression or value, though should never exceed a character’s hit dice in value.

½ BAB Progression: Gain 1 BDB at 4th level and every 4 levels thereafter.

¾ BAB Progression: Gain 1 BDB at 3rd level and every 3 levels thereafter.

Full BAB Progression: Gain 1 BDB at 2nd level and every 2 levels thereafter.

Automatic Misses and Hits

 * A natural 1 on the attack roll, or a natural 20 from the defender is always a miss.
 * A natural 20 on the attack roll, or a natural 1 from the defender is always a hit.
 * A natural 20 from the attacker is always a threat, a possible critical hit.
 * A natural 20 from both the attacker and defender is not a threat, and will simply use the higher value to determine the success of the attack.
 * A natural 1 from both the attacker and defender is not a failure either, and will simply use the higher value to determine the success of the attack.
 * If an attacker succeeds against the defender by 4 degrees of success (20 higher), their attack is a threat, a possible critical hit.

Damage
When an attack succeeds, it deals damage. The type of weapon, spells, or ability used determines the amount of damage you deal. Damage reduces a target’s current hit points.

Minimum Damage
If penalties reduce the damage result to less than 1, a hit still deals 1 point of nonlethal damage.

Strength Bonus
When you hit with a melee weapon, or a weapon with the bow or thrown weapon keyword, add your Strength modifier to the damage result.

Wielding a Weapon Two-Handed
When you deal damage with a weapon that you are wielding two-handed, you add 1-1/2 times your Strength bonus (Strength penalties are not multiplied). You don’t get this higher Strength bonus, however, when using a light weapon with two hands.

Despite being held in two hands bows by default only deal base strength modifier damage, with some dealing more based on the individual weapon.

Wielding a Double Weapon
When you deal damage with a double weapon, you add 1-1/2 times your Strength bonus on the main hand attack (Strength penalties are not multiplied). You still deal normal damage with your off-hand attacks made with a double weapon.

Ability Damage/Drain
Certain creatures and magical effects can cause temporary or permanent ability damage (a reduction to an ability score). More details can be found under status conditions.

Hit Points
All creatures and even objects have hit points, representing how much damage a creature can take before they are knocked unconscious or even killed. Creatures are not impaired by a loss of hit points until their hit points drop to 0 or lower. A character at 0 or fewer hit points gains the disabled condition while a creature at -1 or lower instead gains the dying condition.

Loss of Hit Points
Most attacks that successfully hit will deal an amount of hit point damage. Any time a creature takes damage, the damage is subtracted from their current hit point total.

Disabled
Once a creature’s hit points reaches 0 they are disabled, gaining the staggered condition. This limits the creature to a single move or standard action each turn; but in addition any standard action taken will deal 1 damage to you after the action has completed; this means if the action did not increase their hit points they will be at -1 hit points and begin dying. Move actions may be taken while disabled without causing additonal injury.

This condition is removed as soon as the creature’s hit points are brought above 0 hit points. A creature below -1 hit points or lower that is healed up to 0 can also recover from dying into being disabled again, though additional healing can remove the disabled effect as normal.

Dying
When a creature’s hit point total is negative they are considered dying. A dying character immediately falls unconscious and can take no actions. While dying, and not stable, the creature will lose 1 hit point at the start of their turn each round until they become stable.

Death
A creature dies when their current hit points become low enough to meet or exceed their death threshold.

A creature’s death threshold is their constitution score plus the number of hit dice they possess; for example a creature with a 14 constitution and 4 hit dice would have a 18 death threshold, thus would die a -18 hit points or lower.

A creature may also die if their constitution score is reduced to 0 through ability damage or ability drain.

While death may be the end for most, some types of rare or powerful magic can prevent and even undo death.

Stabilizing
When a creature is a -1 or lower but not yet dead they are considered dying until they are stabilized. At the start of their turn they must make a DC 15 Survival check to stabilize. The creature takes a penalty to this roll equal to the number of negative hit points they are currently at. A creature that is stable is no longer dying, and as such will not lose additional hit points each round, and does not need to make further Survival checks to stabilize. If the creature fails this check they remain dying and lose 1 hit point as usual.

If a stable creature at negative hit points takes damage, they are no longer stable and begin dying again, requiring survival checks to become stable again on their turn.

Other creatures may attempt to assist the dying character and stabilize them with a DC 15 Medic Check.

Healing
After taking damage a creature may regain hit points through natural or magical healing. Creatures cannot regain hit points beyond their maximum hit point toal.

Natural Healing
After a full rest of 8 hours or more or uninterrupted rest, a character recovers a number of hit points equal to the number of hit dice they possess plus their constitution modifier. If a creature instead rests for an entire day and night they instead double the amount of hit points regained this way.

Magical Healing
Potions, Spells, and even some class features may allow for the restoration of hit points. These methods usually are quicker and more potent forms of healing, and as such are usually limited in their number of uses; usually through spell point, material, or monetary cost.

Healing Ability Damage
Ability damage, but not ability drain, returns naturally at a rate of 1 point per full rest, for each affected ability score. Similar to natural healing for hit points, resting for an entire day and night doubles the amount restored this way.

Ability Drain is not healed through this method and usually requires the application of restorative magics or abilities to restore a drained ability score.

Temporary Hit Points
Some effects, such as the second wind ability martial classes are capable of using, grant temporary hit points. These hit points serve as a buffer against damage and any damage taken by the creature is subtracted from these temporary hit points first. Once a creature’s temporary hit points are depleted, any remaining damage in excess of these temporary hit points are applied to their current hit points as normal. Once temporary hit points are lost, they cannot be restored with healing like normal hit points.

Once the effect that granted the temporary hit points ends or is dispelled, temporary hit points granted by that effect go away. Temporary hit points, unless stated otherwise, do not stack with themselves if they are from the same source. Temporary hit points from different sources may stack, but should be tracked separately from each other especially if an effect ends before the others. A creature may decide which source of temporary hit points take damage first should they have multiple sources active at once.

Constitution Adjustments
When an effect would increase or decrease their constitution score, the creature will need to recalculate their maximum hit points from the adjustment.

For example a creature with 4 hit dice gaining having their constitution boosted from 14 to 16 by an effect would gain 4 additional current and maximum hit points due to the 1 higher constitution modifier they now possess. The inverse of this is true as well when a creature with 4 hit dice having their constitution reduce from 14 to 12 would suddenly lose 4 hit dice from their current and maximum hit points due to the 1 lower constitution modifier they now possess.

Nonlethal Damage
Nonlethal damage is a form of damage a creature can take that is not life-threatening, but can still potentially hinder them should they take too much. Unlike normal damage, nonlethal damage is tracked separately from hit points and is healed quickly with rest or magic.

Dealing Nonlethal Damage
Nonlethal damage may be caused by attacks, environmental effects such as heat, or even exhaustion can cause nonlethal damage. When taking nonlethal damage instead of subtracting from your current hit points, it is instead accumulated and tracked separately with a running total of accumulated nonlethal damage.

Nonlethal Damage with a Weapon that Deals Lethal Damage
Unless stated otherwise, any melee or thrown weapon may be used to deal nonlethal damage, but if it lacks the nonlethal weapon property you take a -4 penalty on your attack roll to do so.

Nonlethal, Temporary Hit Points and Damage Reduction
Nonlethal damage is still treated as normal damage for the purpose of its interaction with sources that reduce damage that a creature takes such as temporary hit points and DR.

Excessive Nonlethal Damage
Once a creature’s nonlethal damage is equal or greater than half their maximum hit points they gain the fatigued condition; if the creature is already fatigued, if the creature is already exhausted they instead become staggered. If the creature’s nonlethal damage is equal or greater than half their maximum hit points and also equal or greater than their current hit points they instead become exhausted; if the creature was already fatigued or exhausted they instead become staggered.

Finally if a creature’s nonlethal damage total is equal to their total maximum hit points they become unconscious and no longer gain nonlethal damage, instead converting all further nonlethal damage into lethal damage until their nonlethal damage is reduced or removed in some way.

Healing Nonlethal Damage
Nonlethal damage is healed at a rate of 1 hit point per hour per hiit dice the creature possesses. Spells or abilities that restore hit points also remove an equal amount of nonlethal damage.

The creature loses the fatigued or exhausted condition granted by excessive nonlethal damage if they weren’t already from another source. If the creature had the fatigued or exhausted condition become more severe due to nonlethal damage it returns to its previous level of severity before they gained the nonlethal damage if they did not have the more severe condition already from another source.

Speed
A creature’s speed represents how far they can move with a single move action. Speed primarily is dependent on a creature’s race and armor; some classes or items may temporarily or permanently adjust a creature’s speed.

Moving is usually done through a move action; some actions, such as charging, may combine movement with another action. A creature may choose to take two move actions during their turn to move, or run as a full-round action.

Measuring Distance
In this system distance is measured assuming that 1 square is equal to 5 feet. Thus the terms 5 feet and 1 square may be used interchangeably with each other.

Diagonals
This system uses the “one two one” style of diagonal movement. This means when moving diagonally every other square counts as 2 squares of movement. As such the first diagonal counts as 1 square, second counts as 2, third counting as 1, and fourth as 2, etc.

A creature cannot make a diagonal movement past a corner, but may choose to move diagonally around a creature, or an obstacle such as a pit.

Moving Through Occupied Squares
Creatures can move through squares occupied by an allied or friendly creature without having their movement impeded; with exception the charge action which cannot be impeded by allied or enemy creatures. You do not provoke attacks of opportunity from enemies when moving through an Ally’s square; you still provoke attacks of opportunity from the square you left as well as squares adjacent to the ally that are threatened by the enemy.

You cannot normally move through a square occupied by an enemy creature unless that creature is helpless. You can attempt to use acrobatics to move through a creature’s square, but this may be difficult depending on the creature (see acrobatics skill).

Creatures at least one size category larger than you present an obstacle to you even when helpless and as such are treated as difficult terrain to move through squares occupied by them.

If there is at least one size category difference in size between you and your opponent you may attempt to move into their square, but doing so provokes an attack of opportunity and cannot be done using a 5-foot step.

Difficult Terrain
Terrain that impedes a creature’s movement, such rocky terrain, steep stairs, and undergrowth. Each square of difficult terrain counts as 2 squares of movement, with each diagonal square movement counting as 3 squares of movement. Creatures cannot normally charge across difficult terrain.

When occupying squares with multiple kinds of terrain or difficult terrain, the effects do not stack, and instead a creature is only affected by the most difficult terrain occupied.

Creatures that that are using flight ignore the effects of difficult terrain on the ground even if they occupy the square of difficult terrain. Creatures climbing on walls next to, but not directly on the difficult terrain are treated the same, unless somehow the surface they are climbing on would also be considered difficult terrain. Incorporeal creatures are unaffected by difficult terrain.

Obstacles
Obstacles are usually objects such as a table, chair, waist-high wall, etc. that are in a path of movement, but can be easily stepped over/onto without needing to spend time climbing.

Obstacles can both occupy a square or simply be something that needs to be overcome to enter into the next square. Each obstructed square or space between squares that is obstructed counts as 2 squares of movement. If you run out of movement for your turn or simply do not possess enough speed using both move actions in a turn to cross over the obstruction to the square on the other side, your movement is instead immediately halted before the obstacle.

Some obstacles may simply represent hopping up onto a ledge, table, cart, or similar object where the obstacle is only the movement required to get onto the object or terrain, but once on top of the object movement is no longer hampered, unless it possesses some form of difficult terrain to hamper movement further.

Generally hopping off of an object, such as a table, does not present the same effort or challenge as getting onto it and as such is not treated as an obstacle.

If an object or terrain is too great of a challenge to pass normally, it may no longer count as a simple obstacle and may require a skill check (such as a climb or acrobatics check) to pass.

Similar to difficult terrain, flying creatures may simply fly over or around an obstacle provided there is enough space for them to pass through; while incorporeal creatures can usually ignore most obstacles.

Squeezing
Sometimes an area may not be as wide as the space you take up, and requires you to squeeze through. A creature can squeeze into a space that is at least half as wide as their normal space; with each square of squeezing counting as if it were 2 squares. While squeezing into a narrow space your movement and defenses are hampered, imparting a -4 penalty on attack rolls and AC.

A creature can attempt squeeze into a space less than half their space’s width, using the Escape Artist skill (see the Escape Artist skill), but doing so limits the creature’s movement, making them unable to make attacks, giving a -4 penalty to AC, and are denied their dexterity bonus to AC.

Saving Throws
Many abilities or magical attacks target a creature’s other statistics rather than their AC, and instead attack their reflexes, fortitude, or will directly. Like an attack roll vs AC, both the attacker and defender roll a d20 to determine the outcome of this roll. When a spell calls for a save attack, the attacker rolls the save attack and the defender make an opposed saving throw roll to determine the outcome.

A creature’s saving throw modifier is:

Base save bonus + ability modifier + miscellaneous bonus to that saving throw.

Save bonus is usually determined by a creature’s level and their save allocation (see character advancement for save allocation). From there each type of saving throw has their own ability score tied to them.

Saving Throw Types
The three different kinds of saving throws are Fortitude, Reflex, and Will:

Fortitude
These saves measure physical ability to shrug off punishment and attacks directly against their vitality itself. A creature uses their constitution modifier to determine their Fortitude saving throw.

Reflex
These saves measure your ability to dodge area attacks and other unexpected situations. A creature uses their dexterity modifier to determine their Reflex saving throw.

Will
These represent your mental influence and ability to deal with attacks and suggestions that target the mind. A creature uses their Wisdom modifier to determine their Will saving throw.

Save Attack Roll
A spell or ability usually has a save attack roll associated with it. This is a D20 plus relevant modifiers that make up your Save Attack bonus.

Spell save attacks usually use 1d20 + ½  Spell Prowess Bonus (SPB) + casting ability modifier.

If the save attack bonus is from a special ability of a class or creature it is usually half your class level or half the creature’s hit dice plus constitution modifier, or a different ability modifier as specified by the feat or class.

Other modifiers may exist to boost a saving throw or save attack.

Automatic Failures and Successes
A natural 1 from the defender (the d20 comes up 1) on a saving throw is always a failure for the defender, or a natural 20 from the attacker (the d20 comes up 20) is a failure for the defender as well  (and may cause damage to exposed items; see Items Surviving after a Saving Throw).

A natural 20 from the dfender is always a success for the defender, and a natural 1 from the attacker is always a success for the defender.

If Both the attacker and defender roll a natural 20 it is not considered an automatic success or failure and the final values of both rolls must be used to determine success or failure.

If both the attacker and defender roll a natural 1 it is not considered an automatic success or failure and the final values of both rolls must be used to determine success or failure.

Note a creature may choose to willingly fail a saving throw, this is not treated as a critical failure (such as damaging items for a critically failed reflex save) but you still treat their result as a 1.

Creature Size
Normally creatures of Small or Medium size have a standard reach of 5 feet. For creatures above medium or below small their reach tends to be as is listed in the creature size chart. Listed within this chart are “Tall” and “Long” creatures, this is generally a distinction between creatures that stand upright, or creatures closer to the ground like a wolf, with these general body shapes determining the rate at which their reach progresses as they progress through the sizes.

Creatures Smaller Than Small
Creatures below the size category of small take up less than 1 square of space; allowing more than one such creature to fit into a single square. The general rules is creatures of this size category can occupy 4 of the space that a single creature one size category above them can occupy. As such 4 Tiny creatures can fit into a square, while 16 diminutive creatures can fit within a square, and 64 fine sized creature can fit into a single square. This value doubles if the creatures are capable of flight as they can then occupy the vertical space of the square as well, changing the progression to 8 Tiny, 32 Diminutive, or 128 Fine sized creatures. Usually fine sized creatures within gatherings of this size instead of being tracked separately are instead treated as a swarm.

Creatures that take up less than 1 square of space typically have a natural reach of 0 feet, meaning they cannot reach into adjacent squares, requiring them to enter an opponent's square if they wish to make melee attacks. A creature can always attack into their own square allowing them to attack such creatures normally. A creature with a reach of 0 threatens no squares around them and cannot flank an enemy.

Creatures of Tiny or smaller sized wielding a reach weapon are instead treated as 1 size category larger for the purposes of determining their reach (up to Small). Spells or abilities that improve a creature’s reach (but not size) simply allows creatures of this size to be treated as a size category larger (up to a maximum of Small) for determining reach for every 5 feet of additional reach they receive. Once a creature of this size is treated a small for determining reach they only gain additional 5 feet of reach for every 10 feet of reach an effect would grant beyond this. If an effect would cause these creatures to become small size or larger they calculate their reach and improvements to their reach as normal.

Large and Larger Creatures
Creatures above the size category of medium take up more than 1 square.

Creatures that take up more than 1 square fall into one of two categories of reach progression as “tall” or “long”. Tall creatures (generally humanoid shaped or similar) typically have a natural reach of 10 feet or more, meaning that they can reach targets even if they aren’t in adjacent squares. Long creatures (generally quadrupeds like wolves) only have a natural reach of 5 feet when large and increase to 10 or more at higher size categories. Most creature types and even some spells that modify form may specify or change your type of reach progression.

As the improvement to their reach is granted by their size and not a weapon property, they may attack and threaten all squares within their natural reach, making it difficult to approach such creatures as most medium sized creatures must pass through a square of a creature’s reach before they can get adjacent to it to attack.

When a creature above medium uses a reach weapon you double their natural reach as normal for determining what squares they can attack and threaten with the weapon; but cannot attack or threaten squares within their natural reach unless they change their grip as normal for a reach weapon.

Square Occupied by Creature Three Sizes Larger or Smaller
A creature can move through a square occupied by a creature at least two size categories larger than it without needing to use acrobatics to move through their space. Doing so provokes attacks of opportunity as normal for movement.

Creature Size chart
All creatures above or below medium receive the following bonuses and penalties based on their size. In addition when a creature's size is adjusted they should receive the following adjustments to their strength and dexterity scores. Player races that already start at size categories above or below medium (such as giant and halfling) already have these stat adjustments factored into their racial stat adjustments.

Two-Weapon Fighting
When wielding a second weapon a creature can gain one extra attack per round when making a full-attack action. When making an attack with two weapons the creature must designate which weapon is their main hand and off hand weapon before making attack rolls. The creature suffers a -4 penalty with both weapons when attacking with two weapons. This penalty only applies when making a full attack with both weapons, if the creature choses to make a full attack with only one weapon, or any other action made to attack, they do not receive this penalty. This penalty is reduced by 2 (minimum 0) if at least one of the weapons being used is from the light weapon group.

do not suffer this penalty if you only attack with your main hand and do not make attack rolls with your off hand. This penalty is reduced by 2 for both hands if your off hand weapon is from the light weapon category.

A creature cannot use a limb utilized in a main-hand attack for an off-hand attack; such as using both hands for a two-handed weapon and then releasing the weapon to make an unarmed strike, but the creature could use a bite attack as a off-hand weapon as that was not a limb used to wield the two-handed weapon.

Double Weapons
Double weapons are a type of two-handed melee weapon that allows a creature to perform two-weapon fighting as if they were wielding two weapons by utilizing each end of the weapon. When using a double weapon to make a full attack action you treat each end as if they were a light weapon for the purposes of determining penalties from two-weapon fighting. Most double weapons are exotic and difficult to weild, but are also unique allowing a creature to add 1.5x their strength modifier on damage rolls with the main-hand and 1x on their off-hand attacks made with the weapon.

Combat Modifiers
There are a number of various conditions and scenarios that can influence an attack roll, granting bonuses or penalties to attack rolls or AC.

Attacking From Higher Ground
When a creature attacks from a higher elevation than their target they gain a +1 bonus to attack rolls against that creature. The attacking creature must be at least above the half the target creature’s occupied square (such as attacking while standing on a table or from the back of a mount). This bonus applies to both melee and ranged attacks made when attacking from higher ground.

Cover
When making an attack you must determine if the target has cover from the attack. The attacking creature chooses the corner of your square they wish to make the attack from, and then draws a line to any corner of the target’s square; if any of these line passes through a square or border that would block line of effect or if the creature is partially obscured by an object they have cover, gaining a +4 bonus to AC the attack.

When making a melee attack, if any line from any corner of your square to the target’s square goes through a wall, even including a low wall, the defending creature gains cover from that melee attack. Creatures not directly adjacent to each other making melee attacks, such as through using a reach weapon or being large or larger sized, use the ranged attack rules for determining cover from attacks.

Obstacles and Cover
An obstacle or wall can provide cover, provided it is at least half the height of both creatures' squares (attacker and defender); and only if both creatures are within 30 feet of it. If the wall is half the height of the defender but less than half the height of the attacker’s occupied square (such as a medium defender against a large attacker), they do not gain cover as the larger creature can more easily attack around the obstacle. If the attacker is closer to the obstacle than their target the defender does not gain the benefits of cover.

Cover and Attacks of Opportunity
Creatures are not threatened and thus cannot provoke attacks of opportunity from creatures they have cover from.

Cover and Reflex Saves
If a creature has cover from the origin point of a spell or ability that makes a reflex save attack that creature gains a +2 bonus on Reflex saves against that effect. If the effect originates from a creature, use the normal ranged attack rules to determine cover, but if the effect selects a square of origin to burst out from, the creature instead calculates cover from the point of origin to themselves rather than the creature that created the effect.

Soft Cover
Creatures, both allies and enemies, can provide a lesser form of cover against an attack, granting a +2 bonus to AC, and a +1 bonus on Reflex saves. In addition soft cover does not properly conceal you and thus is inadequate to attempt to make a stealth check to hide.

Big Creatures and Cover
Creatures that occupy more than one square due to their size can choose any square it occupies to determine if an opponent has cover against its melee attacks, potentially allowing them to attack around the cover a creature may have possessed. When being attacked the attacker can choose any square the larger creature occupies to determine if it has cover against their attack.

Total Cover
If a creature is completely obscured and the attacker has no line of effect to the target, they are treated as having total cover, and cannot be attacked.

Improved Cover
When attacking a target hiding behind an arrowslit or any other type of cover that would obscure 75% of more of a creature they are treated as having improved cover, granting a +8 bonus to AC, and +4 on reflex saves against attacks. In addition full cover provides a +10 bonus on stealth checks made to hide.

When making a reflex save attack against a creature that has improved cover against you or the point of origin of your spell or effect the creature only takes half damage on a successful save attack, and no damage on a failed save attack.

Concealment
If a creature is within,  partially within, or near an area of dim light, darkness, fog, or similar type of areas the attacker will need to determine if that creature has concealment from them. The attacker choses a corner of their square and draws a line to any corner of the target’s square; if any of these lines passes through a square or border of an area that provides concealment, the target has concealment from your attack.

Some effects may not be an area but rather may grant concealment to the creature itself; in these situations the creature instead has concealment regardless if any other concealment exists.

Concealment Miss Chance
Concealment normally grants a creature a 20% chance for an attack to automatically miss them. Before the attack is rolled the attacker needs to roll a d100, if their result is higher than the miss chance they may make their attack roll as normal, if their result is equal to or lower than the miss chance the attack is considered a miss even before any attack roll is made. Multiple sources of concealment do not stack. Some effects may grant concealment but grant a different miss chance than the normal 20%.

Total Concealment
When an attack has line of effect, but not line of sight, the defending creature is treated as having total concealment. Creatures cannot directly attack an opponent that has total concealment, and instead must attack a square they think their target occupies. If the attacker picks the correct square they roll for concealment miss chance as normal but rather than 20% the miss chance is increased to 50% for being total concealment. Total concealment can be granted by an area or simply effects that make the creature itself invisible can also grant total concealment.

Creatures that have total concealment do not provoke attacks of opportunity from creatures that they have concealment from.

Ignoring Concealment
Some senses such as blindsense can assist in locating a creature’s square but provide no benefit against the miss chance itself, while senses such as blindsight can potentially completely bypass the effects of total concealment. Concealment granted through dim light or darkness can be ignored if the attacking creature has darkvision, or eliminated should a creature provide a light source to simply remove the darkness. As such it is important to determine any senses, vision, or additional effects the attacker may have when determining if the defending creature has the benefits of concealment.

Flanking
When making a melee attack, a creature may gain a +2 flanking bonus if the target is threatened by another enemy creature on the opposite border or corner. The other flanking creature does not need to be an ally or friendly to the attacking creature, it only needs to be an enemy of the creature that is being flanked. If the creature on the opposite side does not threaten the target they do not provide or gain a flanking bonus.

To determine flanking on larger creatures, draw a line from the center of the two attacker’s squares; if the line passes through opposite borders or corners of the defending creature’s space, then the opponent is treated as flanking. Attacking creatures that occupy more than one square may use any square they occupy as the point of origin for determining flanking.

Mounted Combat
These rules cover being mounted on a horse in combat but can also be applied to more unusual steeds, such as a griffon or dragon.

Mounts in Combat
Various creatures can serve readily as a combat steed, improving the mobility of an attacker. Your mount acts on your initiative count, but still retains its own actions it may use as you direct it. When the mount moves you are moved with it until you dismount from it. A mount unless specified otherwise must be at least one size category larger than the creature riding it. While mounted you are treated as sharing your mount’s space.

Combat while Mounted
When guiding a mount of animal intelligence you must make a DC 5 ride check as a move action to direct it, usually requiring you to hold onto the reins or the creature itself to assist in directing it. If you wish to guide the animal without the use of reigns or your hands so you can perform other actions, it is instead a DC 8 ride check. If you fail this check and your hands are occupied you may always choose to simply not move or guide the mount that turn.

Mounts with greater than animal intelligence can easily follow orders and commands no longer requiring you to use an action to direct it, as it is able to act independently from you.

Melee Combat
When attacking a creature smaller than your mount you gain the +1 bonus to melee as long as that creature is on the same or lower elevation as your mount.

If you direct your mount to charge the enemy you may still make an attack at the end of the charge even if you used your move action to direct the creature that turn, instead using your remaining standard action to perform the charge attack, while still moving with your mount. You and your mount suffer the penalty to AC from the charge as well as gain the bonus to attack rolls gained from the charge.

In addition you may choose to make a ride-by attack allowing you to make an attack as a standard action while your mount is moving. If your mount makes a double move on its turn, it is treated as if there was no delay between movements and as such you may make a ride-by attack during this double move, but are limited to the standard action of the ride-by. If your mount uses the charge action you gain the benefits and penalties of the charge as normal, but you may instead choose to let your mount charge past your target rather than stopping at it; but doing so prevents the mount from making any attacks of its own against the target of the ride-by attack, though it may make an attack against a creature at the end of the charge should one be within reach when it finishes its charge action. The standard action used to make this attack may be used to make an attack action or perform any other action, but melee attacks used in this way take a -2 penalty due to rigorous motion and timing required to accurately hit your target.

You may attack normally without penalty if your attack occurs before or after your mount makes a single move, but not a double move.

Ranged Combat
Making ranged attacks while mounted normally provides no penalty as long as all attacks made are made before the mount begins moving. You may perform a ride-by using a ranged weapon, but unlike a melee weapon may be used to make a standard or full-round action to attack as you have greater range than a melee weapon; in addition you may target any creature within range of your bow during the movement of the horse rather than creatures adjacent to the horse on its path.

The rigorous motion of mounted combat makes it far more difficult to accurately hit a target. If you attack with your ranged weapon during or after your mount makes a double move or charge action, all ranged attacks made this way take a -4 penalty. If the mount took the run action this penalty instead becomes -8.

You may attack normally without penalty if your attack occurs before or after your mount makes a single move, but not a double move.

Certain weapons may gain additional benefits or have restrictions while mounted, check the weapon description for weapons such as longbows and shortbows for details.

Intelligent Mounts
Creatures with an intelligence modifier greater than 2 can serve as mounts but certain rules no longer apply or apply differently.

You and your mount still act on the same initiative, but the creature may use its actions without your direction. If the creature is under your control, such as through a class feature, you may still direct it but it no longer requires a move action to guide it as both words and more subtle communication may be used. If your mount is not under your control it does not need to listen to you and may choose to use its actions regardless of your direction.

Casting Spells While Mounted
You may cast a spell normally without penalty if your spellcasting occurs before or after your mount makes a single move, but not a double move. If your mount performs a double-move, charge, or run action you may still cast at any point during or after this movement, but doing so requires a concentration skill check due to the motion. Casting made during a doble move or charge action is treated as vigorous motion (DC 10 + ½ the BCB of the spell). Casting during or after a run action is treated a violent motion (DC 15 + ½ BCB of the spell)

Your Mount Falls
If your mount falls prone you must succeed a DC 15 Ride check to soften the fall to take no damage. Failing this check causes you to take 1d6 point of damage.

Unconscious Rider
If a rider is knocked unconscious they must roll a d100 to determine if they stay mounted. A mount without a saddle only has a 25% chance to keep a rider, a normal saddle offers a 50% chance, while a military saddle offers a 75% chance to remain upon the mount when unconscious. If your roll is equal to or lower than the percentage chance you stay in the saddle, while all rolls above the chance instead cause you to immediately fall off the mount in a random adjacent square taking 1d6 points of damage. An unguided mount of animal intelligence will usually attempt to avoid combat.

You must re-attempt this d100 roll to determine if you remain upon the mount for each hour you remain unconscious upon the mount.

Bonus Types
This section details the types of bonuses and if they stack. As a general rule, if a bonus type does not stack, but a creature is currently benefiting from multiple of the same type of bonus only the highest bonus type may apply.

Penalties are generally not typed and unless otherwise specified can stack with each other. If a penalty is typed it can stack with any bonuses of the same type potentially lowering or outright negating the typed bonus, but cannot stack with other penalties of the same type, taking the worst penalty of the same type.