Chiguhagu na Karera no Koi no Yukue

Synopsis

Coworkers Tarou Momokawa and Miyuki Amami could not be any less alike. With his dark eye bags and slouched posture, Momokawa is the very stereotype of a gamer; conversely, Amami is a proper woman who would never even touch a gamepad. However, beneath that prim veneer, Amami is well known in the gaming world under the alias "Mermaid," but she takes great measures to ensure no one in real life ever discovers this dual identity. One day, the two seeming opposites cross paths at a live tournament event. This sends Amami in a scramble to maintain her secret at any cost, but the truth is... Momokawa is actually one of her biggest fans?! (Source: MyAnimeList)