Combat Modifiers

Originating from sources such as dense smoke and battlefield position, concealment obscures precise senses and imposes a miss chance on attacks. When you have concealment, it’s harder for enemies to see you clearly. This might be due to your position on the battlefield, or it might be due to another effect that makes it more difficult for enemies to perceive and hit you with an attack.

To determine whether you have concealment from a creature’s ranged attack, choose a corner of the enemy’s square. If any line from this corner to any corner of your square passes through a square that provides concealment or the border of such a square, you have concealment. Also use these rules when a creature makes a melee attack against a target that isn’t adjacent to it.

When a creature is making a melee attack against an adjacent target, the target has concealment if its space is entirely within an effect that grants concealment.

Additionally, some effects provide concealment against all attacks, regardless of whether any intervening concealment exists.

Cover does not necessarily block precise senses, but it does make it more difficult to hit a target. To determine whether your target has cover from your attack, choose a corner of your square. If any line from this corner to any corner of the target’s square passes through a square or border that blocks line of effect or provides cover, or through a square occupied by a creature, the target has cover. Cover grants you a +4 bonus to AC and a +2 bonus to Reflex saves against attacks that originate from a point on the other side of the cover from you. Note that spread effects can extend around corners and negate these bonuses.

When making a melee attack, you gain a +2 bonus to attack rolls if your opponent is threatened (see page 255) by another creature on its opposite border or opposite corner. Only a creature that threatens the opponent can grant this bonus, and your bonus from flanking can never be higher than +2. Creatures with a reach of 0 feet can’t flank an opponent.

When in doubt about whether two characters who threaten an opponent flank it, trace a line between the two attackers’ centers. If the line passes through opposite borders or corners of the opponent’s space, then the opponent is flanked.

Exception: If a creature takes up more than one square, it gets the flanking bonus if any square it occupies counts for flanking.

If you are lying on the ground, you are prone. When prone, you take a –4 penalty to melee attack rolls. You also gain a +4 bonus to your Armor Class against ranged attacks but take a –4 penalty to your AC against melee attacks. If you are knocked down in zero gravity, you’re off-kilter (see page 276) instead of prone.