The Hidden Dungeon Only I Can Enter

Synopsis

The Hidden Dungeon is a place of legend where rare treasures and items are hidden. Noir, the third son of an impoverished noble family who's lost the one job offer he had, was lucky enough to hear about this dungeon. He then acquires a skill that allows him to create, bestow, and edit skills... and in order to use it, he needs to accumulate points by carrying out such tasks as eating delicious meals and doing sexual things with alluring members of the opposite sex.

(Source: Crunchyroll)