Spider-Man is practically the only non-Jerk Ass in Ultimate Marvel. And even he gets his moments. But for more specific examples:
- Flash Thompson, in his Flanderised characterisation, and primarily during high school. Afterwards, he became the Loveable Jock, and one of Peter's close friends, even becoming a heroic Badass Normal soldier, before being crippled. Even with the Venom symbionts, he's a pretty nice guy, and served as the Token Good Teamate on General Ross' incarnation of the Thunderbolts (though when your teammates are The Punisher, Elektra, Red Hulk and Deadpool, this ain't that hard).
- Jean Grey casually abusing her power by switching Peter and Logan's minds (having threatened to do so to Logan, but Peter, being nowhere near the X-Men, had no clue) just because Logan hit on her one time too many for her taste. Peter flatly calls her and the rest of the X-Men out on this, accusing them of being hated not because they were mutants, but because they were complete assholes.
- It should be noted that Jean didn't purposefully do this to Peter. She made it so Logan would switch with the last person he wanted to be and that turned out to be Peter. This arguably makes it worse - she decided some random person deserved to be possessed by Wolverine, and didn't care enough to bother checking who that was.
- And speaking of Logan, the implications of just what he tried to do with Mary Jane while in Peter's body, just for starters.
- Also, let's not forget that Logan deliberately left Scott to die in the Savage Land, just so he could try and get Jean in bed.
- Not that mainstream Wolverine isn't one himself. The guy tried to hit on the already-in a relationship Jean Grey, generally is unpleasant as possible without being violent about it, except when he is, and is a gigantic hypocrite who carries petty grudges and calls people on them whenever he can.
- Hank Pym's wife-beater status may be mostly undeserved in the 616-verse, but boy howdy, does he earn it here. And on top of being a Jerk Ass, he's batshit insane on his bad days.
- Ultimate Daredevil is a complete tool. He's still a good guy, but his methods are a little more extreme and when a disheartened and down on his luck (for a change of pace) Spider-Man asks him for advice, he thoroughly chews him out in the rudest, most dickish way imaginable—something to the effect of "You're a stupid little kid who's in over his head. Get out of this business before you get someone, or more importantly me, killed." Afterwards, several times when Peter came to his aid Daredevil gave him a mild beating and threw him out of the fight. Eventually, when Daredevil hits his lowest point, it's Peter who talks him out of killing an innocent woman just to get back at Wilson Fisk.
- Ultimates 3 turns Hawkeye into a melodramatic, gun-crazy Death Seeker. When he goes to Spider-Man for information after "Venom" attacks the mansion, he gets Spidey's attention by shooting at him, paralyses him with a tranq dart, and then leaves him lying in the snow after getting called back by Cap. Man, Spidey gets this from both teams.
Spider-Man: Hey...uh...guys? Little help here?...I hate you.
- Even Captain America is an asshole. While the original writer merely made him a jingoistic "1940s-average-Joe" type, with all the fish-out-of-water attitude that came with it, later writers added in racism and sexism, just to make him match the rest of the universe's assholery. He eventually has an Asshole Realization when Peter Parker dies, having done so by taking a bullet for Steve, mere hours after Steve had given him a long "The Reason You Suck" Speech about why he was a terrible hero.
- While anything Mark Millar says in interviews can be taken with an entire bucket of salt, he's gone on record saying that this Cap's personality (which he charitably just calls "social conservative") is specifically what makes him cool, in a Die Hard kind of way. Then again, this is the same interview where he compares Cap to Batman in a "He goes in, 3000 people die', and the situation gets resolved" comment, and that no one's ever taken a superhero in the direction he's taken Ultimate Cap, so once more, take it with a lot of salt.