Hatsukoi Made no Unnatural
初恋までのアンナチュラル · はつこい まで の あんなちゅらる
est. Rough estimate based on volume count, reprints and magazine — not an official figure
Overview
Sakuya is not good with scary things. One day, he sees a strange figure in front of his apartment and calls out, only to discover it’s Kyousuke, a senior from his college days. Despite Sakuya's initial fear, he invites Kyousuke in but soon realizes that Kyousuke enjoys teasing and threatening him. To Sakuya's surprise, Kyousuke seems thrilled to learn that the apartment is a "stigmatized property"...!? (Source: Kadokawa, translated) Note: Includes two extra chapters.
Source: AniList
External databases: AniList
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