18+ Boku to Kanojo no Game Sensou

Kishimine Kengo, a boy who moved into a high school that was an all-girls school until several years ago. In spite of the so-called harem environment where he was surrounded only by girls, he wasn't good at socialising and his sole hobby was immersing himself in reading. He lived a quiet life.

But, he decided to participate in club activities that he hadn't done until now, and so his high school life changed into something stormy and full of drama. He joined the one where he played modern games – in short, the game club. Kishimine was supported by the beautiful student council head and a perverted teacher, and he displayed unexpected talent. Now the curtain has been raised on the exciting gaming life of an ordinary boy.

(Source: Baka-Tsuki)