History of Brakion

Brakion, Genesis Mind is a Vex Hobgoblin serving as the Vex Mind of the Pyramidion on Io, coordinating the conversion of the planet into a machine world. He is the final boss of The Pyramidion strike and, per Destinypedia, took Asher Mir's arm after capturing his expedition.

Fight

His head can be shot off to expose a weak point on his chest. He teleports, raises barriers that require light altars to drop, and summons Goblins then Minotaurs.