The Strongest Magician in the Universe in the Concave and Convex World

It Doesn't Matter If It's an Embossed Article of Either Gender, with or Without CP, but It Must Be Strong.

It's nothing, right? It's just a concave and convex novel. It can be of any gender, with or without CP, but it must be strong. There's nothing to read on the bookshelf recently. If there is no concave and convex world, then concave and convex academy is also acceptable.