The March of Ages
Krolovik asked Samuel to save her, Samuel replied that he could, but that she wouldn’t be the same. Krolovik told him to do it, and Samuel prevented her soul from departing, and shackled it to her corpse. She reanimated, but as a succubus. Samuel initially tried to have her feed on blood, as he did, but over time she realized she could feed more effectively on strong emotions through sex.
While alive, she could make people love her with her magic. This power changed to the preternatural ability to incite lust as an undead creature.
Derrigan hates undead, and has made his opinion that she is an abomination clear to the Voltierran council, but they chose not to act and he has not acted against her independently.