The game was developed by Spike Chunsoft and Atlus, the developers of the Mystery Dungeon and Etrian Odyssey series, respectively, with most of the actual development done at Spike Chunsoft, while Atlus acted as supervisors.
Atlus USA, the American subsidiary of Atlus, began work on an English localization of the game before development had finished, resulting in an English release only a month after the original Japanese release.