Hellbound knight( Champions of Ruin, p. 23)
A devoted disciple of the Nine Hells, you have sworn to strike down creatures that oppose law and threaten tyranny.
Disciple of Darkness (CoR) , base attack bonus +4,
Any weapon you wield is treated as lawful- and evilaligned for the purpose of overcoming damage reduction. In addition, against chaotic outsiders, you gain a +1 profane bonus on attack rolls.
This feat can only be taken once. A character who takes this feat cannot also take the Demonsworn Knight or Tormented Knight feat. A fighter can select this feat as one of his fi ghter bonus feats. In addition, as soon as you take this feat, your eyes turn red.