Unlike his mainstream counterpart, Ultimate Colossus is gay and does not have a romance with Ultimate Kitty Pryde/Shadowcat. This is implied during the Mark Millar's run on the title, through his interactions with fellow X-Man Wolverine (this is implied during the "Return of the King" story arc, in which Colossus almost beats Magneto to a pulp when he threatens Wolverine). It is implied (through stereotype) when Jean Grey reveals to the readers that Peter's favorite TV show is "Will & Grace", but stated more directly in that the main reason Colossus left the X-Men might have been that he was unable to make the X-Man he'd fallen in love with love him, even in the slightest. Storm also suggests Peter is gay when Angel arrives at the school and Storm explains to him that the reason that all the girls "and "maybe" Colossus" stare at him is because he is good looking. It is more openly addressed later during a series of mutant murders by Sinister, Colossus tends to the wounds of Northstar, the only survivor. He is shocked when the openly gay Northstar asks if Colossus is single, which triggers a transformation into his metal state.