Primordial Scion( Fiendish Codex I: Hordes of the Abyss, p. 87)
The Abyss beckons . . . .
any one Abyssal heritor feat, Chaotic alignment,
Your natural weapons, as well as any weapons you wield, are treated as chaotic-aligned for the purpose of overcoming damage reduction. In addition, attacks you make with such weapons deal an extra ld6 points of damage to lawful creatures. This bonus increases by an additional ld6 for every four Abyssal heritor feats you possess.
Because of the chaotic whispers in your head, you take a -2 penalty on Listen checks.