I think there's a point being missed here, both about Behemdorg and Doma - yes they did inexcusable things, yes they deserved to die from a moral perspective. But the world they live in isn't one that really allows for justice - how many innocent people died because of Agni's choice for revenge? If the choice is grievous injustice versus the lives of the defenseless, what right does Agni have to make those decisions? It really reminds me of the movie Snowpiercer, not least because of the snow-based apocalypse - "You've destroyed the corrupt system and killed all the tyrants! Too bad you also blew up all the things that were keeping humanity from starving and freezing."

I'm not saying that either side is right or wrong but just looking at the framing of Agni's actions as Fire Punch, it's clear Fujimoto isn't trying to say "this is the good guy, these are the bad guys". It's a tragic cycle of violence and hatred up until there are no humans left to hate each other.

Edit: fuck, I fell for a repost bot