The Hero with a Thousand Faces (The Collected Works of Joseph Campbell)

That's because you don't understand narrative structure. Read these books if you have time: ​The Hero with a Thousand Faces by Joseph Campbell <<< the majority of the manwhas/mangas follow this exact structure with their protagonists Story: Substance, Structure, Style and the Principles of Screenwriting by Robert McKee 7-Point Story Structure Story Engineering by Larry Brooks