Your knowledge of vampires has given you the extraordinary ability to detect subtle signs of their presence and to resist their dominating gaze ability.
Prerequisite: Knowledge (religion) 6 ranks.
Benefits: You can take a move action to unfailingly determine whether a vampire or vampire spawn is within 30 feet of you. In addition, you are immune to the dominating gaze ability of vampires and vampire spawn.
Source: Libris Mortis, page 31.