The Forever Song - Julie Kagawa

Allison Sekemoto once struggled with the question: human or monster?

With the death of her love, Zeke, she has her answer.

MONSTER

Allie will embrace her cold vampire side to hunt down and end Sarren, the psychopathic vampire who murdered Zeke. But the trail is bloody and long, and Sarren has left many surprises for Allie and her companions--her creator, Kanin, and her blood brother, Jackal. The trail is leading straight to the one place they must protect at any cost--the last vampire-free zone on Earth, Eden. And Sarren has one final, brutal shock in store for Allie.

In a ruined world where no life is sacred and former allies can turn on you in one heartbeat, Allie will face her darkest days. And if she succeeds, triumph is short-lived in the face of surviving forever alone.