Mujihi na Yoru ni
無慈悲なヨルに · むじひな よる に
est. Rough estimate based on volume count, reprints and magazine — not an official figure
Overview
Note: Includes "Warui Koto Shitai Series: Bangai-hen (ワルイコトシタイシリーズ 番外編)" and one extra chapter.
Source: AniList
External databases: AniList
How to compare editions, collected volumes and ISBNs / Sources, updates and corrections