MultiVersus' Iron Giant isn't a pacifist because the game is set in an "alternate universe".
The latest character to be revealed for MultiVersus was the Iron Giant, one of Warner Bros. most popular animated icons. Although many fans reacted happily seeing him appear alongside his idol Superman, many others were annoyed that a character known for his pacifism and refusing to be a weapon was suddenly duking it out with the rest of the cast.
As reported by PC Gamer, MultiVersus' game director Tony Huynh spoke about the reasoning behind why the Iron Giant was suddenly so ready to punch things up in the game. According to him, MultiVersus is an "alternate universe", which sets up all of the characters to be a bit more violent and ready to fight than they usually would be. Huynh also references "different Iron Giants" as a possible reason why the character is fighting.
Huynh said, "So, first of all, we're starting with this being an alternate universe. Characters are pulled in from all over. And also if you understand the Iron Giant lore, there are multiple Iron Giants. And it's an assembly line of different Iron Giants. So that being said, the backstory on the website is that Iron Giant is learning from Superman, who is his idol. And Superman uses his powers to protect people. And our game is inherently focused on co-op and protecting your ally."
Huynh also said that the team had heard the criticisms and was willing to work alongside them, although he also noted that the character and his moves hadn't yet been revealed, "We want to take these types of criticisms into account. So if that doesn't satisfy, we'd like to hear it, but I think a lot of the game mechanics and the character haven't been revealed yet, either. So that might help as well."
The character description for The Iron Giant on MultiVersus' site reads, "With no memory of his past and no clear direction for his future, he was found by a young boy named Hogarth Hughes, who quickly became his best friend. Loyal and brave, the Iron Giant is a defender of the innocent and has vowed to always emulate his hero: Superman."