Reign Or Shine Demon Princess Series, Book 1.

Nikki Donovan has enough trouble fitting in at her new school without the weird guy who keeps following her around. And when he approaches her, claiming to be sent by her long-lost father, Nikki finds out the truth: the father she never knew is the demon king of the Shadowlands- the realm between our world and the Underworld-and now that he's dying, she is his sole heir to the throne. Maybe it's because she's in shock, or maybe it's because the m...