(V) = Villain
Ice Warrior: Hero wannabe armed with ice sculpted weapons.
Icesis: (V) Sorceress with magic ice powers.
Ignoramus, The: (V) Villain that has based his persona on Jerry Lewis’ Nutty Professor. He is known at times to wear a propeller hat, which onlymakes him all the more odious.
Igore: (V) Hunchback assistant to Young Casanova Frankenstein.
Ill Eagle: (V)
Imaginary Man: With his battle cry of"awesomerific!", he fights his evil arch-nemesis/sister, NemeSIS.
Impastainator: (V) Italian villain that is the master of pasta.
Impressionist, The: (V) Snobbish art criminal and connoisseur that can mimic anyone’s voice. He was initially a hero.
Insectia: (V) Teen insect queen. Member of the Varsity Villains Squad.
Inspector #12: (V) Former quality control inspector of clothes that has turned evil.
Investor, The: (V) Former accountant and day-trader known for his financial mischief. Member of the Lefthanded League.
Invisible Boy: Teen hero that can turn invisible but only if no one actually looks at him. Member of the Mystery Men.
Invisible Guy: Permanently invisible hero that wears his clothes out of modesty, he is assisted by his invisible dog, Spot.
Irma-Geddon: Armored powerhouse, sister to Ertha Quake.
Irregular Four, The: Second rate super hero group based in Capitol City, only called if everyone else is unavailable. Members are The Human Stapler, Mister Microphone, Seiko, and Weather Woman.