You should know that this world is chaotic and lawless. By day, Headless Horsemen rampage through Ikebukuro; by night, demons and spirits roam in a hundred-ghost parade. Urban legends known to everyone in the glittering metropolis devour lives; terrifying monsters in the deep, mysterious forests manipulate people's hearts. Well-dressed people commit horrifying blood sacrifices for the sake of a little extra life; ignorant villagers throw anyone who doesn't fit in into the abyss. In the sky, stars from hell are heading your way; in the ocean, Earth's liege is about to awaken; underground, the immortal lizard is about to destroy the world.
Why do you still fight? Why can't you cry? Why can't you despair? Why do you still want to save humanity?
Because I'm a hero, even if I'm retired.
P.S. The story of a retired hero punching the Old Ones and kicking the Outer Gods.