Venus, planet of love, was destroyed by global warming

Dabi as a kid was cheerful, however, it got ruined by his father. He ruined Dabi's...well, Toya's sparkle in eyes and heart. He was responsible for Toya being a villain under name of Dabi.

Dabi didn't even want to be like this, but it's too late and he doesn't care.

He was even toxic without realising.