The Shadow Trials by Juliana Haygert

A demon hunter destined for greatness. A half-demon out to solve a mystery. And a tournament that threatens to take their lives…

Erin
Everything at the academy has changed. A bloodthirsty new headmaster has taken over the school, and my friends and I are being forced to endure his relentless torment.
Besides getting through my classes, I’ve got a huge burden on my shoulders. My father, King Brikan and lord over all demons, is rising in power. To defeat him and save the supernatural realm from the terrors of the underworld, I need to find my missing sisters… a task that’s proving impossible.

Rey
I’ve never been freer in my life–and at the same time, never been more trapped.
Erin and I have to be on our guard. Students are being attacked, and there’s a traitor in our midst.
Even worse, Erin and I are both forced to enter a tournament due to our demon blood. All half-demons must prove they are worthy enough to attend the academy by enduring a deadly contest. One I’m not sure we’ll survive.
But nothing is what it seems, and the answers to all our mysteries are lurking in the shadows…