Aubrey is a higher level vampire within the ranks of the regime of Nikolaos, the master of the city, but despite his age he is not a master. Because of his sporadic behavior, he was often punished my Nikolaos, which made his mental condition even works. Aubrey is now partially insane and won't hesitate to attack someone who makes him angry.
Aubrey blackmails Anita Blake into investigating the series of vampire murders by entrancing her best friend with his mind.
He attacks Anita in Guilty Pleasures and she is saved by Jean-Claude.