Amon

Amon is a fallen, rogue Xel'Naga in the StarCraft series, revealed in Heart of the Swarm as the master of Samir Duran. He seeks to destroy all life in the Koprulu Sector and remake it in his own image, and the Protoss-Zerg hybrids of the series were created as part of his plans. In Legacy of the Void his forces, including the Moebius Foundation, attack Korhal and the Dominion, and he seizes the Khala to control the Protoss through their nerve cords. Only a fellow Xel'Naga can kill him, so Kerrigan ascends to become one and destroys him in the Void with the joint Terran, Zerg and Protoss armada.