Sneak Attack
At 3rd level, if a slayer catches an opponent unable to defend itself effectively from his attack, he can strike a vital spot for extra damage. The slayer’s attack deals extra damage anytime his target would be denied a Dexterity bonus to AC (whether the target actually has a Dexterity bonus or not), or when the slayer flanks his target. This additional damage is 1d6 at 3rd level, and increases by 1d6 every 3 levels thereafter. Should the slayer score a critical hit with a sneak attack, this additional damage is not multiplied. Ranged attacks can count as sneak attacks only if the target is within 30 feet.
With a weapon that deals nonlethal damage (such as a sap, a whip, or an unarmed strike), a slayer can make a sneak attack that deals nonlethal damage instead of lethal damage. He cannot use a weapon that deals lethal damage to deal nonlethal damage in a sneak attack, not even with the usual –4 penalty.
The slayer must be able to see the target well enough to pick out a vital spot and must be able to reach such a spot. A slayer cannot use sneak attack while striking a creature that has concealment.