Evil the Cat is the manifestation of evil. He rules over the volcanic Planet Heck (residing elsewhere only for the hottest months). Molding Heck to his own vision of evil perfection, the planet is covered with spiked walls and precariously placed cliffs and ridges. The planet is also full of fiery pits and drops, which Evil has filled with all things evil he's found across the universe, ranging from Shadow Demons and rabid Lawyers to elevator music. Evil wants to claim Jim's Super Suit as his own, to further conquer the galaxy and paint it more infernal.
Over the course of the cartoon series, which makes up its own particular canon, Evil concentrates more on destroying the universe rather than obtaining Jim's suit (even though one episode began with Evil stealing Jim's suit in an attempt to destroy him). He has been continuously thwarted by such forces as origami, the Department of Apocalyptic Affairs, and even the cartoon's budget running out. "A minor setback" is Evil's usual response to his misfortunes. He is frequently assisted, but more often annoyed, by his aide Henchrat.
In spite of his status as a purely evil villain, Evil occasionally shows the behavior of a real cat, such as licking himself or playing with a ball of yarn when he's bored. In Earthworm Jim, he'll actually stop to groom himself a bit in between shots of his huge fireball gun.
As befitting of his status as a ruler of a hellish world, Evil is affiliated with fire. In the first game, he attacks Jim by shooting fireballs at him from an enormous flamethrower, which cause fiery shockwaves. After said shockwaves erode the base of the platform he is standing on, causing it to collapse, he resorts to pouncing on Jim while wreathed in darkness. Those attacks are also accompanied by fiery shockwaves from the left and right. He "dies" in one shot, but must be "killed" nine times to be defeated for good - a reference to the popular saying that "cats have nine lives."
According to the instruction manual for Earthworm Jim 2, Evil has a cousin named Flagitious, who runs "The Circus of the Scars". During Heck's summer off-season, Evil switches jobs with Flagitious and runs the circus himself.
In the animated series, Evil will try to disguise himself to try to get close to Earthworm Jim, and will often interject "Did I mention, I'm not a cat?". He is voiced by Edward Hibbert.
In "Evil in Love", an episode of the animated series, Evil the Cat fell in love with a fellow villain named Malice The Dog. However, she abandoned him at the end of the episode to star in her own television series.
He also has the most appearances out of all the villains in the animated series, appearing in almost every episode, except for The Anti-Fish, Darwin's Nightmare, The Exile of Lucy, Peanut of the Apes, and For Whom the Jingle Bell Tolls.
As his name implies, Evil the Cat is pure evil. Said to be born with no heart, he is the eternal ruler of the volcanic planet Heck, a personification of evil. Wherever there is good, it is his job to eliminate it! Because he is immortal, Evil can never be destroyed. However he can be temporarily defeated...his ways and past are shrouded by myth and darkness.
Evil is armed with vampire-like razor fangs. He can also spit out hairballs covered in his stomach acid. His most dangerous weapons however is his scythe-like talons which can slash through almost anything.