The unsuccessful adventurer "Zalmen" decided to retire from adventuring. Furthermore, to graduate from being a virgin, he decided to squander all the assets he had diligently saved since being reincarnated in a high-class brothel. Appearing before him was a top-tier woman with whom he'd likely never have had a connection in his life. Thanks to her hospitality, Zalmen fully enjoyed his first sex, but at the moment he finished, a mysterious announcement echoed in his ears: "Implantation confirmed. Level up!" "Could it be that... I get stronger the more I 'breed'...?" A bottom-tier adventurer who was level 1 for years rises to the top through sex—an extraordinary implantation-style Isekai adventure fantasy!