After his visit to the Angoulême International Comics Festival in France, Mashima revealed that the new series would be "a new form of fantasy", and that the character Plue from his earlier series Rave Master would appear in the manga.
Setelah kunjungannya di Festival Komik Internasional Angoulême di Prancis, Mashima mengungkapkan bahwa seri ini merupakan "sebuah bentuk baru dari cerita fantasi", dan bahwa karakter Plue dari seri terdahulunya bertajuk Rave Master akan muncul di manga baru ini.