Darkling Penitentiary by Stephany Wallace

Tonight, I killed the Queen of the Starlight Faeries… my grandmother.

I am Zenevieve, the Starlight Princess, and with one glance you’d think nothing else of me, yet there’s another side that no one knows. From the age of five I’ve secretly trained in the dark arts, foreseeing that one day I would be summoned by the God of the Realms.
So, when a burning rose appears on my pillow, I know I’ve been chosen.
Accepting my new purpose means losing the only family I’ve ever known, earning a one-way ticket to Darkling Penitentiary. Nevertheless, my mission is bigger than all of us. But there is one obstacle I didn’t anticipate, the monster who rules the prison, and in order to fulfill my destiny I’ll have to eliminate him.
The issue? He appears to be the only creature immune to my deadly light.