Blood Warrior — H.D. Gordon

When her home is attacked by murderous vampires, 17-year-old Alexa is forced to leave her mother for dead in order to save her sister. She soon learns that she is the last known member of an elite race of supernatural Warriors, and is thrust into a world full of vampires and werewolves who all seem to regard her as some sort of savior. Meanwhile, Alexa battles a monster within herself that seeks to gain control; a monster that seeks blood. The hidden city she finds herself in appears perfect, but Alexa's instincts tell her that all is not right within its walls. When she is asked to attend a school of fighters, whose exams consist of gladiator-style competitions, she must decide who she can trust among the smiling faces. And, when she meets Kayden, a vampire she feels undeniably drawn to, she must decide if she can trust herself.