Quintet Company, Limited (株式会社クインテット, Kabushiki gaisha Kuintetto) is a Japanese video game developer, founded in 1989. The company name is derived from musical terminology, as well as 5 elements of game design - planning, graphics, sound, programmers, and producers. Quintet was most active in the 1990s, when it had a strong relationship with Enix (now incorporated into Square Enix); the company was also a member of GD-NET group of Sega Saturn developers. The current status of Quintet is unclear.
Source: Wikipedia, "Quintet (game developer)," available under the CC-BY-SA License.