Defiant Rebellion by Candace Wondrak

Fighting evil was not something I signed up for when I accepted a position at Grimmstead Academy, but here I am.
This house is alive, and its mouth is hungry. Chaos flows from it, causing every soul stuck here to be mad. Ian, Dagen, Payne, Koda, Bram, and Lucien—their weaknesses all stem from one man.
Victor Grimmstead.
Victor is back, alive and walking through the halls as if he’d never left. Can he be trusted? The jury’s still out. But it’s not time for uncertainty; it’s time for rebellion, to fight the supernatural power keeping us here. This game will finally end, even if it means I have to give everything to end it.
In Grimmstead, you can’t trust yourself. You can’t trust anyone. The blood, the insanity, the confusion—it all leads to a choice none of us can take back.
Once caught in the web, it never lets you go.