Two Me: a Loser and a Monster!

A different kind of fantasy! Unique flavor and full of fun! The two mes switch smoothly and cooperate with each other! One is a loser who is doing nothing, and the other is a strong man who keeps counterattacking. Which one is the real me? You are a waste! No, I'm not! You think I am useless, but in fact, I am frighteningly strong! The writing is light, the people are multifaceted, and the story is important! No time travel, no harem, anti-routine, not anti-intellectual, light humor!