Bound to the Snake Spirit

Something was crawling under my skin. Mocking the Willow Clan Spirit, I was entangled with Severin, a 430-year-old Snake Spirit. It said I was marked by a Violent Spirit, won't live past Winter Solstice, and must become its Vessel. Following Severin to eliminate the evil spirit, the Department of Paranormal Investigations showed up. This revealed a crazed 800-year-old Snake Spirit and Severin's banishment secret from the Willow Clan. All this drags me into a deeper abyss.