Whenever the character makes a successful attack against an opponent who is Flat Footed, cannot see them, or who is in combat with someone else, the character's blow delivers extra damage. This extra damage is 1d6 at Scout Level 2 and 2d6 at Scout Level 4, 3d6 at Rogue Level 2, 4d6 at Rogue Level 4, 5d6 Rogue Level 6 and 6d6 at Dervish Level 2. This extra damage is not multiplied in the case of a critical hit. Use: Automatic. Monsters of the construct and undead types are immune to sneak attacks, as are any creatures that are immune to critical hits. Dervish granted this feat at Level 2