That main character was already powerful or intelligence or at least in one 'ability' of talents.
In any genre, (Mostly shounen but can be some shoujo)
In first few chapters that person had shown that person already strong enough to beat few or many people in beginning of few chapters. Or person realized that they has a talent in something and its very good.
It's can be come from hard work, natural talent, gain the talent, or hide talent.
Just a compilation of well made porns with no good plots but top notch dicks *laughs in fetishes
[Just to warn the wandering hornd's , the mangas containing rape plot have warning "■RAPE WARNING■" to avoid having readers who hate rape plots unintentionally read it. <they're on the latter part and pretty minimal>]