Dareka no Sekai
ダレカノセカイ · だれか の せかい
est. Rough estimate based on volume count, reprints and magazine — not an official figure
Overview
As Yukari Kagono approaches graduation, a strange faceless creature attacks his city. Anya, a mysterious girl, appears before him, and tells him that he is a creator, a person with the ability to materialize things from nothing, and is the key to defeating the strange apparation.
Source: AniList
External databases: MADB · AniList
How to compare editions, collected volumes and ISBNs / Sources, updates and corrections