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 a creature is threatened by another enemy create on opposite borders or corners they gain the flanked condition. The flanked condition imparts a -2 penalty to the target’s AC rolls against all attack rolls against it, not just from creatures flanking it. Flanking represents a creature’s inability to properly defend themselves from attacks coming from multiple directions at once. Both creatures must have the ability to threaten the creature for them to cause this.

As flanked is a condition applied to the target creatures besides the creatures causing the creature to gain the flanked condition still treat the target as being flanked when making attack rolls against it, regardless of their range or condition.

To determine flanking on creatures larger than medium, 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 target 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.

Some abilities may allow creatures to treat a target as being flanked or apply the flanked condition to a target.