After the release of the third "Final Fantasy" title in 1990, Square offered designer Koichi Ishii to direct a spin-off series game. It began development for the Game Boy under the working title "Gemma Knights"; eventually, Square revived the trademarked name and released the game as "Seiken Densetsu: Final Fantasy Gaiden". It was later released in Europe as "Mystic Quest". Ishii suggested the basis of the game's story, while scenario writer Yoshinori Kitase helped write the game's script. Ishii designed all of the characters himself, while Goro Ohashi was responsible for the development of the game system.