Aku no Onna Kanbu 1

It is based on the pornographic video game Lune. Katsuma is just a go-getter for his female superiors... Whenever he engages in combat with Silverstar, a hero, he is victorious. His superiors appear out of nowhere and trap Katsuma and Silverstar just as he is about to engage in another battle with Silverstar. As soon as he regains consciousness, he discovers that he is being looked after by Maria, another Silverstar. She attracts Katsuma's attention because of her compassion... no, he merely sleeps with her... By sleeping with her, he, on the other hand, gains a unique ability... He gradually comes to the conclusion that he must get vengeance on his superiors...