Bosses
Duriel
Greater boss in Kehjistan. Hoard opens with a Greater Lair Key.
Where and how
His lair is the Gaping Crevasse, east of Gea Kul in Kehjistan. The hoard takes one Greater Lair Key.
Unique pool
Mythic drops from this hoard come from this pool. See Lair bosses for how mythics work.
Three more items can drop here: Rage of Harrogath (Barbarian), which the Bloody Butcher can also drop; Rod of Kepeleke (Spiritborn), which Astaroth can also drop; and Morlu Fleshward (Warlock).