The Beastlord is a fearsome creature held in high esteem by the cultists in the Great Rock, including Bearnath. The Beastlord allegedly lives on another plane, and can be summoned onto the Prime Material Plane through a blood ritual, requiring the Chalice of the Beast.
The Beastlord appears similar to a bear, but its head is shaped more like a badger, and it walks upright on massive paws. He is referred to as the cultists' Master, and Bearnath would seek to rule Sapience with the Beastlord's help.