Voiced by Tom Papa
- Anything That Moves: He has no qualms with having sex with monsters.
- All Men Are Perverts: 98% of the time he's focused on wanting to have sex with attractive women.
- Cool Car: Drives a red convertible with flame decals and tail fins.
- Doorstop Baby: He was taken in by Suzi X's family when he was just an infant in a basket left at their front door.
- Everyone Has Standards: Incest is a line he will not cross, even if his sister isn't biologically related to him.
- Foolish Sibling, Responsible Sibling: The Foolish to Suzi's Responsible.
- Retired Badass: He is a former wrestler.
- Sanity Ball: Grasps it near the end of the movie when he finds out someone just happened to be carrying a book that had all the info needed to stop Dr. Satan the entire time and finds it ridiculous it wasn't mentioned sooner.
- Small Name, Big Ego: He thinks he's the best hero there is, but is often making a mess of things.
- Unsympathetic Comedy Protagonist: A lot of humor is derived from how self-centered and rude he is.
Voiced by Sheri Moon Zombie
- Action Girl: She fights monsters.
- Anti-Hero: The monsters she fights are evil, but she tends to be unrelenting in the level of violence she's willing to use against them.
- Barbie Doll Anatomy: Avoided. Her nipples are clearly shown a few times.
- Buxom Is Better: Like with almost every female characters she has large breasts.
- Eyepatch of Power: She wears an eyepatch for an unknown reason and has had it since she was a little girl. Even Lampshaded by the singers in her theme song.
- Ms. Fanservice: She's very gorgeous and gets several nude scenes.
- Guns Akimbo: Her primary means of attack is dual-fisting automatics.
- Hartman Hips: She has wide hips.
- Heroic Comedic Sociopath: She really enjoys inflicting violence on monsters.
- Jerk with a Heart of Gold: Heroic sociopath she may be, she's never rude or condescending to Murray and views him as invaluable help even if she doesn't realize he's in love with her.
- Oblivious to Love: Murray is hopelessly in love with her, but she seems to view their relationship as Just Friends.
- Stripperiffic: She is first seen wearing a very revealing costume.
- Spy Catsuit: Partway through the film, she changes into a form-fitting bodysuit.
- Vapor Wear: She even admits not wearing panties.
Murray the Robot
Voiced by Brian Posehn
- Do-Anything Robot: He can turn into different vehicles and he also has several weapons built into him.
- Gag Penis: He has a telescoping robot dick which is also a cannon. And a merry-go-round.
- Sex Bot: He's perpetually horny and hopelessly in love with Suzi.
Voiced by Paul Giamatti
- Abhorrent Admirer: He's been an unwanted suitor to Suzi ever since high school.
- Camp Straight: He has some flamboyant tendencies, but he's clearly shown to be into women and has married 22 times before the events of the film.
- Caught with Your Pants Down: Otto walks in on him while he's having A Date with Rosie Palms.
- Dreadful Musician: Back in high school, he wrote a love song to Suzi-X called "Lick My Love Muffin."
- Eats Babies: Shortly after gaining demonic superpowers, he breaks into a delivery room and eats a newborn baby.
- Heterosexual Life-Partners: He and Otto the Gorilla are rather close.
- Kick the Dog: In addition to the above-mentioned baby eating, he crushes a box of kittens under his heel during his demon-powered rampage.
- That Man Is Dead: He had his name legally changed to "Dr. Satan" and insists that "Steve Wachowski is no more!"
Velvet Von Black
Voiced by Rosario Dawson
- Buxom Is Better: She can even control her large breasts to make balloon animals and punch.
- Ms. Fanservice: She is nearly naked for most of the film.
- Gag Boobs: Her breasts can increase to ludicrous sizes.
- Gasshole: She farts a few times and refuses to apologize for it.
- Gold Digger: Marries Dr. Satan for his money.
- Hammerspace: She keeps a pack of cigarettes and a lighter in her cleavage.
- Hartman Hips: She has big hips.
- Interspecies Romance: Has sex with Otto the Gorilla at the end.
- Jerkass: Very obnoxious and foul mouthed.
- Lady Swears-a-Lot: Virtually every line she says is laced with profanity.
- My Girl Is a Slut: A lot of men like her for how lecherous she can be.
- Pretty Fly for a White Guy: She's lily-white, and talks like a Jive Turkey.
- Stripperiffic: Her job was a stripper after all, so of course she'd wear revealing clothes.
- The Von Trope Family: Her surname is Von Black
Otto the Gorilla
Voiced by Tom Kenny
- Everything's Better with Monkeys: He's a sapient ape.
- Heterosexual Life-Partners: He and Dr. Satan act like close friends.
- Hypercompetent Sidekick: Thanks to his head-bolt, he's highly intelligent in addition to his natural strength and agility.
- Non-Human Sidekick: He's a gorilla who also happens to be Dr. Satan's lackey.
- Servile Snarker: Gets in a few pretty good asides at Dr. Satan's expense.
- Slap-Slap-Kiss: Develops this sort of Relationship with Velvet Von Black.
- Wicked Cultured: He enjoys watching BBC documentaries and is an accomplished sculptor and chef.