Optimatus (voiced by Charlie Adler) is Zadavia's evil brother. Optimatus is a mysterious character who possesses similar, if not exactly the same, powers and abilities as Zadavia. He has a cybernetic eye due to an accident on Freleng which resulted in him getting caught in the heat of the jet Zadavia tried to escape on, for which she claimed to be sorry about.
At the time the Loonatics first season in the year of 2772, he resided on a ruined planetoid which he used as his base of operations during all of his Loonatics appearances (It is not made clear whether this is in fact the remains of his futuristic home world of Freleng or just somewhere he set up base after tracking down his sister, however Zadavia states that Freelang is located in an alternate Galaxy and the planetoid was located at the edge of the Loonatics's Solar System). He appears in the final moments of "The Comet Cometh" to state that the meteor's striking Acmetropolis in 2773 was actually a deliberate attempt to destroy Acmetropolis, as was the 500 times smaller first meteor that the episode involves. With both attempts failed, he also states that he plans to attack the planet a third time in the future. In the two-part season-ending episode "Acmegeddon," Optimatus appears again to fulfill his promise, freeing Massive, Mastermind, Sypher, and Weathervane to aid his attempt to defeat the Loonatics. He also entices them by claiming that he will allow them to rule Acmetropolis if they succeed. After he made up his mind that the criminals he had freed "failed" him, he revealed his latest plan to destroy Acmetropolis: sucking it up into a wormhole. He then sends the criminals back to Acmetropolis, saying they can still "rule for five minutes". In the end, however, he and his Optiforce (apparent remnants of robots who served him on his homeworld) are eventually defeated, and he is sucked into one of his own wormholes. Zadavia says he will end up on a dark, cold, deserted part of space and he can then be seen huddling up to a fire, on a small piece of what was once his command center, using the remains of his Optiforce to keep the fire going. He swears he'll get his revenge, but was completely disarmed upon his defeat, making a return next to impossible. He has appeared in the second season finale thanks to Rupes Oberon using Zadavia's stolen powers on him. Rupes Oberon later locates Optimatus and frees him. Both of them then locate Deuce and invade Blanc in an attempt to use Blanc's wormhole technology to conquer the universe and seek out Tweetums' scepter. He was double-crossed by General Deuce and had to fight alongside the Loonatics, Zadavia, and Sylth Vester. In the end, he renounces his evil ways and he and Zadavia return to Freleng as its rulers