Shoujo Golem to Rika-shitsu no Henjin-tachi

Overview

Hatano is a normal high school girl who finds Reimu Iwashita, a beautiful transfer student, entering her class one day. Hatano grows suspicious when Ishida and Kamiya, two otaku in her class with communication problems, act friendly with Reimu. Following the three to the old school building, she comes to learn an unexpected secret about the transfer student. (Source: Asahi Shimbun Shuppan, translated)

Source: AniList