Hinterland by Logan Spurgeon

Kestrel awakes in the woods without a real name or his memories. Before him are twelve strangers, an altar on fire, and bones hanging from the trees like wind chimes. He’s to be initiated into their group so they may fulfill their purpose: head to the mountain of the so-called gods, have a feast, and bring about the end of the world. Kestrel is willing to risk it all to escape, but without any memories, he knows he must play along until he finds a way out.

It won’t be easy. Winter is on their heels, hunters are searching for them, and the strange rituals they perform will rip his humanity from his flesh. But Kestrel isn’t alone. One of the strangers claims to be his friend from before, and there are others willing to join his side and leave the wilderness... if the gods let them.