Richelle Mead 
Succubus Heat [EPUB ebook] 

Georgina Kincaid has been a bad, bad succubus…which should be a good thing. But she’s in a foul mood after breaking up with her boyfriend Seth and has been so wicked that ber-demon Jerome decides to ‘outsource’ Georgina to a rival — and have her spy for him in the process.Then Jerome is kidnapped, and all immortals under his control mysteriously lose their powers. With her life-sucking ability gone, Georgina finds herself caught up in a sinister plot. Is she the only one who can stop all Hell breaking loose?