The Regressor Makes Everything

Lee Se-hoon, the blacksmith of humanity's last suicide squad, fought against the demons to the bitter end, but the result was mutual destruction, the destruction of the world. The moment he took his own life, overcome by that absurdity, he exclaimed, "what is this?" He returned to his days as a trainee at the hero training institute Babel. A new opportunity. He would use anything to achieve victory. Anything!