Nehemus

Son to the Plague Lord, Nehemus Versiles was a human rogue, bent on making his dead father proud. Upon finding out that his father had become undead, his whole world, his entire perspective of reality changed. He was changed from a kind-hearted individual into a cold-hearted silent killer. Nimorrax personally trained Nehemus day and night while the Forbidden were busy with other things.

Eventually, Nehemus came to murder his father to pave a path for Putrud's onslaught. Under his influence, Nehemus had no choice to resist, ensuring the downfall of the Forbidden. However, the Forbidden did not die there... not completely.

After his pathetic failure, Nehemus went into hiding, hidden from all eyes and ears. Waiting. When news of Nimorrax's death spread, Nehemus entered Death's Ocean and took the place over, leading his father's people. He was not trusted, but the Forbidden followed him anyway.

Due to a time reversal, Nehemus tried a new tactic. He siphoned forces very carefully and unknowingly from the Forbidden to his own city on a distant world called Nebulan. There, within the Nebulous Valley, Nehemus constructed Death's Valley. A tribute to Death's Ocean. Once the Void war was over, the remaining Forbidden elites joined up with him on Nebulan and continued their wars.

His reign would not last forever, though. After the war of the gods, the Templars of Virtue came in full force to Death's Valley. Having been on the planet for just about as long as Nehemus and unaffected by the war, they plowed through the streets of Death's Valley, slaughtering every Forbidden in their path. Bruteus personally executed Nehemus aboard Zerteramus. As a last act, Nehemus unleashed a terrifying creation upon the Nebulous Valley that consumed the Templars, both factions would have died out.

Corruption
100 years after his downfall from the Templars, Nehemus had been resurrected by an unknown force and manipulated by what appeared to be a mask. The mask had changed Nehemus into a horseman of the apocalypse, yet different from the typical horsemen. Nehemus rounded up Erebos, Izlinigh and a man named 'Weiss', creating the other three horsemen. The four horsemen then prepared to negate the prophecy entirely but were stopped by none other than the Forbidden, who had been rebuilding on Azeroth for quite some time.