Gruppo One was a Japanese developer that was founded by Katsumi Togashi sometime around the year 2000. The company solely created games for Windows based PCs and was most well known for their series of roguelike RPGs called Kaze no Tansakusha. A majority of the staff that contributed to Gruppo One's games, including Togashi himself, were former Nihon Falcom employees that all left the company in the late 1990s and early 2000s.