Yomizuka no Kaii-san
Synopsis
Yomizuka Junior High School is in a rural town. In it is a strange school club called the Mystery Verification Club. The club has two members: Toramaru, who has chuunibyou, and Miko, who is more normal. But their club activities, which began out of mere curiosity, eventually begin to involve all kinds of people...?! (Source: Kadokawa, translated)
Background
Yomizuka no Kaii-san is an adaptation of HIJIKI's browser game of the same title released on Dwango's RPG Atsumaru service in 2017.