Brothers Chris and Tim Stamper have both left the British game studio, which wasfor $375 million in 2002.
The Redmond, Wash.-based software maker confirmed the departure in a statement, but did not give a specific reason why the two are leaving.
"After more than 20 years, Chris and Tim Stamper have decided to leave Rare to pursue other opportunities," Microsoft said. "We thank them for the many years they have contributed to the Rare brand and wish them luck in their future endeavors."
Microsoft said that 19-year Rare veteran Mark Betteridge will lead the development team as studio director. Gregg Mayles, who helped create Rare's recent title, will serve as creative director.
The departure of the Stamper brothers was reported earlier by enthusiast Web site 1up.com.