General Immortus is an immortal man who is part of the Brotherhood of Evil.
Little is known of the life and career of General Immortus before he joined the Brotherhood, but he has been commanding troops in various battles going back to Pharaonic Egypt. According to Mento of the Doom Patrol, Immortus is a master tactician as a result of his millennia of combat experience in virtually every major world conflict. Judging by his uniform and his human troopers' outfits, it is conceivable that the last military power Immortus had served was the German Nazi party in World War II.
At some point of time Immortus joined the Brotherhood of Evil, contributing his vast resources he had accumulated throughout the millenia, including his own private army of thugs and robots. As a military master strategist, he and the Brain were gradually able to work out the standard modus operandi of their principal enemy in modern times, the Doom Patrol. In the end, they managed to capture and disable their enemies, but Mento had a messenger probe programmed to find to ex-member Beast Boy, who led his new team, the Teen Titans, on the search for his former surrogate family. Eventually, the combined teams defeated the Brotherhood's latest scheme involving a black hole generator.
General Immortus subsequently participated in the Brain's plan to eliminate young superheroes around the world. When the time to strike had come, he personally led the capture of the heroine Argent. During the final battle against the assembled Titans in the Brotherhood's headquarters, however, Immortus and his army were washed away by Aqualad and Tramm, and as the first of the Brotherhood leaders he was flash-frozen as the Titans' victory trophy.