The Hero Life of a (Self-Proclaimed) Mediocre Demon! manga volume 8 features story by Shiroichi Amaui with art by Konekoneko.

Long ago, the Sun King gifted the vampires his power, enabling the vampires to freely walk in the light of day. However, suddenly that power has been taken away and Sofia, along with all of her people in the Vampire Kingdom are now in danger of perishing if exposed to sunlight! In order to help the vampires, Chrono and his friends must find the Sun King in his dungeon and demand satisfaction!