Malduke was the evil Kajeat who instigated the Dark War in 75,000 BBY. He was the first Death Child, as one of his parents, who were First Generation Kajeat, died in the birthing process. He grew up an enigma among the other Kajeat, who didn't know what to make of him.
Malduke was incredibly talented and intelligent, even by Kajeat standards. When he determined that the Kajeat were meant to rule the universe, he was able to sway countless followers to his side. When his attempts to take over failed, he proliferated First Races technology to many of the younger races, raising armies to his cause in exchange for technology and promises of power. He also used his great intelligence to create a weapon that would destroy a Kajeat.
The Dark War raged for centuries until the combined forces of the intergalactic community were able to destroy Malduke's weapon, defeat his forces and capture Malduke himself. They sentenced him to an eternity in isolation, imprisoning him on a remote world and constructing the Galbagos Nebula to prevent anyone from ever finding him.
Malduke spent nearly 75,000 years in complete isolation. Unable to die and without need of sustenance due to his immortality, coupled with no contact with anything outside his small, padded cell, he went completely insane.
He was discovered by the New Imperium when they sent ships in to explore the Galbagos Nebula. Though searching for Altarin'Dakor strongholds, they found none, instead happening upon the world upon which Malduke was imprisoned. Feigning that he was a spacefarer who had recently been trapped there, he convinced the NI forces to release him. He then managed to travel to Varnus, where he spent several months wandering around, seemingly aimlessly.
He then vanished, and was still assumed to remain at large.