Manga where multiple reincarnators compete to kill a demon king. MC has skill steal cheat, and main side character has super growth cheat

Question

There's an isekai fantasy manga where the main character (mc) is reincarnated into a world where there are multiple reincarnators all trying to defeat/kill the demon king (dk), because a deity promised to give the person that kills the dk one wish (I think. Might be thinking of another manga).

Anyway, the mc gets a skill steal ability and meets a guy that has (I think) a super growth ability. But because the super growth guy is innocent/ignorant to the ways of the world, the mc decides to protect that innocence/ignorance.

(As a R18 manga, I think I remember the mc fornicating with a receptionist because he thought she had bad intentions and, spoiler,

I think she did.)

Answer 1

Are you looking for isekai NTR?

The MC follows the "hero" character who is your typical good boy and ignorant. The MC fornicates with women (even the ones that would normally end up as the Hero's harem) and steals the powers, all in the name of protecting the MC and allowing him to grow to be able to kill the demonking.