His Wicked Talismans

Her mother told her never to open it. Valdemeer Academy is about to make that impossible. Three men are bound to the talisman around Octavia's neck: the heir whose family forged it, a forest-ward raised by the thing inside it, and a scholarship student who has heard its voice since he was twelve. The faculty want the talisman for its death magic. Adrian's family wants it back. The forest wants its god released. And Octavia's mother, who died at Valdemeer, left her a talisman with one instruction: don't give it to anyone. So Octavia doesn't. She gives it to the three men who won't hand her over either. The god never left. It just needed a better keeper.