Gilead’s priest was the high priest serving Gilead, a late Jaredite king who was the brother of Shared and who built up his army through secret combinations. The priest murdered Gilead as he sat on his throne (Ether 14:9).
He was then killed by Lib, a member of one of the secret combinations, who murdered him in a secret pass and took the kingdom for himself. Lib was a man of great stature, taller than any other among the people (Ether 14:10).