General Immortus is the lead tactical expert of the Brotherhood of Evil.
In the Teen Titans animated series, there are scenes of Immortus commanding troops in various battles going back to Phaeronic 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. His uniform and the uniforms of his foot soldiers resemble those of the WWII German Army, implying that he may have been a Nazi.
It is not clear if the animated series Immortus is actually immortal, or has just been using his life extending potion for thousands of years, although the former is more likely (Immortus says, in regard to the Doom Patrol, "Persistent, yes. But not immortal.")
During the final battle, he and his army was washed away by Aqualad and Tramm. Soon he was flash-frozen in "Titans Together".