Needs review
Source: Book of Vile Darkness

Description: The character can focus evil power into her weapon blows.

Prerequisites: Weapon Focus, CHA 15

Each time the character deals damage with a specific kind of weapon, she deals 1 additional point of vile damage.

Special

A character may take this feat more than once, selecting a different weapon each time.

This is a Vile feat. Only intelligent characters of an evil alignment can use vile feats. Vile feats are granted to characters at the behest of a powerful evil agency—a god, a demon, or something similar. As such, vile feats are supernatural abilities rather than extraordinary abilities. Some DMs may also want to require a character who seeks a vile feat to perform a special ritual or make an actual bargain with a powerful creature of evil. The patron creature may even (at the DM’s discretion) have the ability to revoke the feat should the character displease it.