Huntress in New Orleans (Book 9, TVD/TO)

Nicola Salvatore was turned into a Huntress three years ago, with urges to kill all of her friends and family. (her ancestors Stefan and Damon that were more like brothers, and her friends Caroline and Enzo, before Stefan killed Enzo). She had to watch her sister Sarah die in front of her, having to give herself over to a Siren named Sybil just to remain in control, and Sybil made her kill her ex boyfriend Tyler Lockwood. Nicola had her humanity off when she sold herself to the Devil named Cade, and killed for him so that he would control her enough to make sure that she didn't kill anyone else she loved ever again, but he instead made it where he would bring Stefan and Damon back from the dead each time she killed them, which was a lot, until their deal was broken when Stefan was made human. After that, Cade tried to do everything in his power to make Nicola lose control, so she had to kill him instead. When Stefan cured Damon of being a vampire so Nicola didn't have to be afraid of killing him again, he also killed himself in a way of killing Katherine Pierce once again, leaving them both alone. Now, Nicola has to learn how to control herself on her own, and with the help of Elijah and the Mikaelsons, maybe she can finally do it.