Its severed head can be returned to one of the collectors in the Society Strongholds in exchange for xp, a title, and a Mana Forge Key.
Tch'Keryk the Emissary says, "Sssoon, very sssoon, we will be poised to crusssh the defilersss of our landsss..."
Your assault sends Tch'Keryk the Emissary to an icy death!
As he dies, Tch'Keryk the Emissary howls at [Killer's Name], "T'thuun take you! Missserable creature!"