Artist had been suffering from pancreatic cancer, recently canceled manga series
While Square Enix‘s announcement did not include a cause of death, Kayaharuka had been suffering from pancreatic cancer since at least 2019. Kayaharuka‘s manga adaptation of Shu‘s The Misfit of Demon King Academy: History’s Strongest Demon King Reincarnates and Goes to School with His Descendants (Maō Gakuin no Futekigōsha ~Shijō Saikyō no Maō no Shiso, Tensei Shite Shison-tachi no Gakkō e Kayō) light novel series was canceled last week so that Kayaharuka could undergo treatment, but Kayaharuka had already passed away at the time of the announcement last week on Wednesday, July 7.
In Kayaharuka‘s statement about the cancelation of the manga, they said that while they regret that the manga had to end this way, they will treasure their time working on it.
The manga launched in July 2018 on Square Enix‘s Manga Up! website, and Square Enix published the fourth volume on March 5. Square Enix Manga & Books publishes the manga in English, and it published the third volume in English on January 26.