The League of Super Evil (abbreviated as L.O.S.E.) is a league of so-called "villains" who star in the show of the same name. They live in Metrotown, a world of super heroes and super villains, but L.O.S.E. is seen as not-so-evil in comparison. Their main plots consist of pulling childish pranks on citizens and trying to take over the neighbourhood, rather than other villains of the show who plan to do more destructive plots.

Members of L.O.S.E.

Voltar - The leader of L.O.S.E. He is a pint-sized character with a high-pitched voice, reminiscent of Invader Zim. He wears a red uniform and helmet which he is almost always seen wearing (he once had a paper bag over his head when his helmet was stolen, so his real face has never been revealed). Voltar is arrogant and haughty and thinks of himself as being superior to everyone else. He may also be paranoid of some things, such as his neighbor Steve, which often causes his "evil" childish schemes, which often fail. He may have been named after the philosopher Voltaire.

Doktor Frogg - An evil genius/mad scientist and the smartest of the group. He helps with the evil plots by creating inventions or mutations, which often fail horribly. Dr. Frogg is considered to be unlucky as many episodes show him getting eaten, attacked, electrocuted, or crushed, leaving him with some near-death experiences. He has metallic claws for hands, which are terrible at grasping objects. He is also very skinny and weak. Dr. Frogg is considerably more evil than the rest of the gang, who plans to rule the earth, as opposed to Voltar's more childish plots.

Red Menace - The muscle man of the group. Despite his size, he is kind, cheerful, and fun-loving, he also enjoys gardening and animals. He is not considered very "evil", though he tries to be.

Doomageddon - He is a pan-dimensional doomhound who serves as a pet to the members of L.O.S.E. He has many different mystical abilities, though he is usually seen changing his size and transporting himself to different places, and can disappear into a portal leading to an alternate otherworldly realm. He has a huge appetite, as he may eat anything from small animals to random objects. He is commonly seen attacking or trying to eat Dr. Frogg, with whom he has a frenemy relationship.

Henchbots- Two crudely-made robots who always fall apart. They serve as the henchmen of the group.