Zhylaw

Zhylaw, also known as The Lord Marshal, is the primary antagonist in The Chronicles of Riddick.

He was the sixth Lord Marshal who was the commanding leader of the Necromongers until he was killed by Riddick.

Pre-History
Prior to the events of the story, Zhylaw was known be a warrior that became part of the Necromongers uprising. Following the death of the fifth Lord Marshal, Zhylaw became the sixth Lord Marshal and was commander of the Necromongers.

Unlike the previous five Lord Marshals, Zhylaw had adopted the Necromongers darkest philosophy when he was told that he would be killed by a Furyan. Because of this, Zhylaw used his position to wipe out a great number of Furyans and anyone who he viewed as a threat to his philosophy.

On this occasion, Zhylaw had travelled across a mysteriously dimension called "Underverse" and, upon returning, had lost his humanity and sanity, becoming someone who's fate was equally half alive and dead; allowing him to experience unnatural powers that made him excessively dangerous.

History
Zhylaw was first seen at the very beginning of the film when the narrator explained the history of the Necromongers that seeked to accomplish Zhylaw's purpose of converting everyone to his faith, and killing those who refused to do so.

He later sent his Necromonger army to conquer a planet called Helion Prime and maintain the territory by taking the entire populace hostage. After it's successful, he and the Necromongers presented themselves in a cathedral where The Purifier, Zhylaw's right-hand priest, explained the origins of the Necromongers in an attempt to persuade everyone into converting. They refused, however, and, one male citizen began criticizing the Necromongers for attempting to coerce the populace into converting, until Zhylaw demonstrates his powers by taking the man's soul with his hand, unnaturally killing him and enabling the rest of the people into kneeling before him.