Looking for isekai novel, where the chuunibyou patient is actually the supreme grandmaster of the darkest of dark annihilation chaos flame or something. any recommendation?
To Be a Power in the Shadows! ? For what I remember he is a chuunibyou and the real thing? The Tv serie Legion its also similiar for what you want
Tilea's Worries is what you want. MC is super OP, but thinks they are normal and everyone else is chunni. But in reality they are the real thing, just even their ultimate attacks are nothing to the MC. So MC sets out to try to fix their chunni while at same time becoming the leader of them as well.
https://www.novelupdates.com/series/chuunibyou-demo-koi-ga-shitai/ Delusion Real? Check supreme yada yada darkflame? Check classroom? check transfere? no check