KANZEN FUKACHI NO GEDOU TAMER: DUNGEON NO SAIKYOU MONSTER MUSUME WO ORE NO SKILL DE SHIHAI SURU

A plain guy named Katsuki who wants to have sex with monster girls suddenly has a portal to another world appear in his home! Beyond the door lies the deepest floor of a dungeon ruled by top-tier monster girls in a brutal survival-of-the-fittest world...!! Armed with a completely undetectable "total invisibility" skill, Katsuki — despite being Level 1 — boldly ventures into the deadly dungeon in pursuit of monster girls!! He sneaks up on monster girls, plays tricks on them, and tames them without being noticed! The birth of a villainous tamer!! (Source: Takecomic, translated) — Description from AniList community (anilist.co).