Bound By Runes by Katherine Scheirer

Fifty years ago, the Mages sacrificed their magic to form a barrier against the Void – a chasm of darkness that releases creatures of the night that consumes everything in its wake. Under the protection of the barrier, those that live in Kingdom of Draydon grieved the lives that were lost, but eventually life resumed.
Lilith was sure that her future would be simple. She would follow her brother’s footsteps and attend the same magical academy as them. Unfortunately, she is at the centre of a prophecy that results in most of her powers being bound by an ancient rune curse.
Trying to hide from the lord that cursed her, Lilith is sent to Skilheim, an elite military academy, where she learns how to control what’s left of her magic and try to figure out how to undo her curse. While trying to survive, she meets the prince, who has taken an interest in her, and against her better judgement she can’t help but be pulled in by his charm.

Just as she gets a handle on her new found life, things become more complicated as the barrier that once protected from the Void breaks.