One of comics’ most asked questions is, who wins in a fight between the Avengers and the X-Men? While the fans got an answer in the pages of Avengers vs X-Men, that doesn’t stop them from imagining all the ways the X-Men and Avengers could clash. However, a decade before Avengers vs X-Men hit the shelves, Mark Millar and Chris Bachalo provided their own answer in their Ultimate X-Men story arc, “Ultimate War.” While it was not the two teams' first battle, it has definitely become one of their least mentioned.
Unlike the events of AvX, in which the two titular teams were fighting for the fate of the Phoenix Force, the central conflict for “Ultimate War” is based a little closer to Earth. After the events of the premiere Ultimate X-Men story arc, “The Tomorrow People,” Charles Xavier wipes the mind of the X-Men’s greatest foe, Magneto -- who is depicted in the Ultimate universe as more of a power-hungry mutant terrorist than an honorable, if not radical, mutant freedom fighter.
After regaining his memories, Erik uses Charles’ mercy and a well-timed attack on S.H.I.E.L.D.’s Triskelion headquarters to manipulate Nick Fury and his agents into believing the X-Men and the Brotherhood were allies from the start. This sends the X-Men into hiding with the Ultimates -- the Ultimate universe iteration of the Avengers -- hot on their trail.
The situation comes to a head when Magneto tips S.H.I.E.L.D. off to the X-Men’s location, leading to an all-out brawl in the middle of the Lower East Side of Manhattan. The Ultimates breach the X-Men’s safehouse alongside multiple S.H.I.E.L.D. teams equipped with neural disruptors to take Xavier and Marvel Girl out of the fight, thus officially beginning their titular war.
In an effort to cover for their classmates as they try to get to safety, Storm and Colossus take on Thor and Iron Man. While Storm overestimates how well she can fare against the God of Thunder, the man of iron learns he’s no match for organic steel as Colossus overwhelms Tony Stark through sheer force.
While these battles take place outside the safehouse, Beast and Professor X are pursued indoors by Hawkeye, Black Widow, and two squads of S.H.I.E.L.D. agents. Hawkeye ends up fighting holograms in the mutants’ makeshift Danger Room while Black Widow -- like the MVP she is -- manages to successfully detonate the X-Jet in midair. This allows Iron Man to catch the young Mr. McCoy and his professor as they parachute to the ground.
Unfortunately for Tony, he fails to detect Wolverine’s approach before the Canucklehead turns his armor into scrap metal. Back inside the safehouse, Jean Grey -- her powers still disrupted -- and Kitty Pryde find themselves cornered by S.H.I.E.L.D. agents ready to pull the trigger until Logan crashes down from above to defend them. As he eviscerates these soldiers, he’s confronted by his old army buddy, Captain America. Cap uses his knowledge of their past together in World War II to gain a tactical advantage and take Wolverine out of the fight in a barrage of gunfire.
With the rest of his team incapacitated, Colossus singlehandedly goes toe to toe with Thor himself and it eventually takes a localized nuclear warhead, fired by Hawkeye, to finally put Rasputin down. Things seem finished for the X-Men until Iceman, who’d been in hiding with his parents, returns to the team atop a 500-foot tall wave of ice and incapacitates the agents and their neural inhibiters long enough for his fellow X-Men to escape from S.H.I.E.L.D. custody. Charles Xavier himself, however, is neutralized and detained by the Ultimates’ own resident mutant, Janet Van Dyne a.k.a. the Wasp.
Who came out on top in the war between the Ultimates and the X-Men? The conflict ends with the Ultimates largely incapacitated and the X-Men on the run, but maybe the X-Men would have fared better if their leader, Cyclops, had joined the fight. Though with Charles Xavier in the hands of S.H.I.E.L.D. and Magneto setting the stage for his most ambitious plan yet, in the end, the one who won the fight between Earth 1610’s mightiest and its most uncanny heroes was really its greatest villain.