OK so I'm gonna state something that is purely from my belief. I understand their anger at how the world turned against them, but to take people's lives especially when they're innocent is uncalled for. Also the new hero or the hero of revenge, is becoming exactly what he hates, which I'm pretty sure he knows. I feel bad for them because they desperately saved people and had people from different worlds love and care for them, only to be monsters in the world they wanted to go back to. I think they're all on the grey with a light shade of black. Their backstory doesn't justify their actions but it makes us understand their anger and why they did what they did. I think I like how this shows that they are neither good nor bad, and that the world simply shaped them through the use of despair. I don't really think it's poorly executed if the authors point is to show people that villains aren't truly villains and heroes aren't truly heroes. Just people driven to a certain madness and extent. I like this it has potential!