Umm yeah love ya and all Iruma but a lot of future issues coulda been avoided if you just let him kill himself
That's just plain false and wrong on so many levels. The amount of contradiction in a single sentence is honestly amazing. You love Iruma, but you think he did the wrong thing by acting like Iruma in this situation? Would we accept an Iruma that lets people die so easily? That wouldn't be Iruma, therefore, that would not be the Iruma you claim to love. Iruma represents the "light" of this story. The story DEPENDS on Iruma being who he is, therefore, the story would suffer greatly if Iruma ever commits an action, or through inaction, permits something that goes against his principles to happen.
Also, you don't really know if a lot of future issues could've been avoided with this guy's death. For all we know, his death causes the downfall of our hero and his friends. We'll never know, since I doubt the author will ever write a canonical "what if" scenario.
And that's why modern super hero movies all suck.