Koichi Ishii (石井 浩一 Ishii Kōichi?, born July 9, 1964), sometimes credited as Kouichi Ishii, is a video game designer perhaps best known for creating the Mana series (known as Seiken Densetsu in Japan). He joined Square (now Square Enix) in 1987, where he has directed or produced every game released in the Mana series (as of 2006). He has also contributed to several games in Square Enix's SaGa and Final Fantasy series, and created the well-known chocobo and moogle characters.
Koichi Ishii directed Final Fantasy I, II, and III, as well as SaGa Frontier. He was invited to work on the original Final Fantasy in 1986, and helped develop the crystal theme that became a recurring motif of the series. Ishii became the head of Square Enix's Product Development Division-8.
He wanted to create a game called "Seiken Densetsu" in 1987, but Square rejected the idea before he even finished planning it. He was able to develop it in the early 1990s as a Final Fantasy Gaiden. He was involved in the development of the Sword of Mana and all other World of Mana games.
The World of Mana series was conceived to be a way for players to experience the Mana (series) in many formats and gameplay styles.
On Heroes of Mana, development of an Real-time strategy game became so difficulty they had to start development all over at one point. Another challenge of game development was due to the Japanese gaming audiences lack of familiarity with an RTS style of gaming. The world of Seiken Densetsu 3 was chosen due to its plot involving warring states, which was thought to be well suited for an RTS game.