The world's foremost superhuman strike force, the Ultimates trace their origins back to World War II sper-operative Captain America (Steve Rogers), whom the U.S. government empowered in part to oppose the Nazis' secret extraterrestrial Chitauri allies. Rogers appeared to die while helping destroy the Chitauri/Nazi war effort, and U.S. scitentist tried for decades to duplicate his powers. In recent years, the super-soldier program's lead scientist was genticist Bruce Banner, reporting to General Ross, head of the S.H.I.E.L.D. intelligence agency. Later, new expansion of the super-soldier program, though Banner's temporary transformation into the monstrous Hulk resulted in his demotion to deputy under new head scientist Hank and Janet Pym, who did double duty as size-changing super-operatives Giant-Man and Wasp. Altruistic armored billionaire inventor Tony Stark soon joined as Iron Man. Enigmatic left-wing powerhouse Thor refused membership at first, but Captain America himself was found alive and revived from a state of suspended animation to join the team. Together, Rogers, Stark, and the Pyms became the Ultimates, headquartered in the high-tech Triskellion complex and backed by a huge support staff, a large conventional military force and black ops agents. Banner's semi-estranged girlfriend Betty Ross (daughter of General Ross) was hired as Directed of Communication and helped make the new team into celebrities while making Bruce's life miserable. The depressed Banner finally snapped and transformed into the Hulk again, embarking on a destuctive rampage stopped by the Ultimates with the aid of Thor, who began working with the team thereafter. The Hulk's true identity was concealed from the public, and the Ultimates became beloved national heroes. The group soon expanded intelligence veterans Hawkeye and Black Widow and mutant ex-terrorists Quicksilver and Scarlet Witch were promoted from the black ops division to the core team. Meanwhile, Hank Pym nearly killed his wife during a violent domestic dispute and was himself beaten into a traction by Captain America, who later becan dating the Wasp. Pym's former assistant Dr. Eamonn Brankin became the new scientific head of the program. Despite losing Giant-Man, the Ultimates saved the world from a Chitauri plot with the unwitting aid of the Hulk and became bigger icons than ever. They went on to apprenhend Kraven, Electro, Luther Manning, the X-Men, and Norman Osborn's "Six". Later allied with the European Super-Solider Initiative, the Ultimates became more controversial as they began operating in foreign territory, notably the Middle East. Thor quit, and a traitor within the group outed Branner as the Hulk. Seemingly executed for the Hulk'crimes, Banner secretly survived with the aid of Hank Pym, who was soon fired form the Ultimates altogether. Meanwhile, apparently exposed as a madman, Thor was brutally arrested by the team. The global community grew wary as the Ultimates developed many more superagents as their reserves, and anti-Ultimates sentiment accelerated when the team stripped a small "rogue" Middle Eastern nation of its nuclear capability. The traitor within the Ultimates responded by murdering Hawkeye's family, framed Captain America for the crime, and helping a foreign super-army invade America. Assisted by Hank Pym, this foreign force destroyed the Triskelion and occupied major American cities, slaughtering the reserves and capturing the remaining Ultimates in the process.
The Ultimates managed to defeat the Liberators, with the help of Thor and Odin. But after the battle, the members decided that they no longer wanted to be used for government services, after seeing what an impact they had on the residents of the countries they attacked. They decided to operate independently, financed by Tony Stark, without any help from S.H.I.E.L.D.