Koichi Mashimo co-wrote and directed the microseries, while Bee Train and Production I.G animated it, and Bandai Entertainment acted as the North American distributor. The full-length anime series was handled by director and writer Mitsuru Hongo and was animated by Production I.G, with Bee Train returning for in-between animation. Production I.G president Mitsuhisa Ishikawa joined on as producer for the series. It was the first time he had worked on a joint U.S. Japanese production, due to the "Pokémon" companion franchise.