- The Ultimates:
- The team is more of an elite military unit than a group of noble superheroes, groomed to fight the controversial War on Terror. In-Universe, views are conflicting: people in America see them as Eagleland Type 1, but for foreign powers they are a Type 2.
- Betty Ross was created as a sweet girl that fell in love with Bruce Banner, in stark contrast with her father, "Thunderbolt" Ross, an always-angry General Ripper. The Ultimates take preference for her Military Brat aspect instead.
- Captain America, unlike his mainstream counterpart (who is the example for Incorruptible Pure Pureness most of the time), isn't just a man from the 1940s, he's abrasively rude and holds many of the same bigoted views prevalent at the time. He also lacks the main Cap's diplomatic side, which was clear when he was elected president: he told state governors to solve their disputes between themselves instead of asking for his mediation, and when a state tried to secede from the Union he forced it to stay in it... the manliest way possible. He regularly dismembers and kills his opponents, as a cinematic trope usually employed in Ultimate Marvel is that Superhero Movie Villains Die.
- Hank Pym in the main universe has his issues and hit his wife once in a fit of rage, but never escalated beyond that and has spent years trying to make up for it. Ultimate Hank is a repeated abuser and once attacked her with an army of ants while she was shrunken down (after he gassed her with bug spray). He put her into a coma with this stunt.
- Hawkeye is a cold black-ops agent, instead of the jokester of the main universe. It only gets worse when his family dies, when he becomes a Death Seeker who antagonizes the rest of his team.
- Pyro initially started off as a case of Adaptational Heroism, helping other people and joining the X-Men. Then came Ultimates 3, where he infamously did something that got his hands cut off and Mastermind beheaded, and would appall even the classic Pyro — suggesting he and Mastermind rape Valkyrie.
- Ultimate Spider-Man:
- As opposed to the classic Betty Brant, this Betty was a general jackass to people, including sleeping with Kraven, throwing around Ned Leeds's drinking problem to get a story she wanted and making bets about Ben Urich's disappearance. And during Miles Morales's time, she died before she could "out" Jefferson Morales as the second Spider-Man, not caring about how it'd affect Rio or Miles.
- In the mainstream comics, Flash Thompson started as The Bully, whose only purpose was to make Peter's life at school miserable. Eventually he got a more sympathetic characterization, join the army and even became a superhero of his own. Ultimate Flash Thompson, on the other hand, stayed in the original characterization and never grew beyond it.
- Ultimate X-Men:
- Professor X compared his love for his son to that of a pet owner and their pet, and was willing to create a drug made from Wolverine's DNA.
- Because he was among Weapon X's victims, Nightcrawler had a brief psychotic break where he was a Stalker with a Crush to Dazzler and homophobic towards Colossus, though he later made amends.
- Magneto was outright genocidal, and lacked the 616 version's tragic Holocaust backstory to boot. Also, while the mainstream Magneto won't be winning any Father of the Year awards anytime soon, Ultimate Magneto took this Up to Eleven, constantly berating Quicksilver and humiliating him in front of the other Brotherhood members. He once even asked Cyclops to refer to him as "Father" in front of Quicksilver just to further crush the boy's spirit.
- Dazzler is openly rebellious and prone to swearing, since this version of her has more of a Punk Rock theme than Disco.
Adaptational Jerkass / Ultimate Marvel