Rare, Ltd.

From the Super Mario Wiki

Rare, Ltd.
Founded	1982
First Mario Game	Donkey Kong Country
Latest Mario Game	Diddy Kong Racing DS

Rare, Ltd. (also known as Rareware and simply Rare) is a British video game company who currently make games for Microsoft's XBox 360 and Nintendo's Game Boy Advance and Nintendo DS. They are responsible for games involving Banjo and Conker. Before Microsoft bought rights to Rare, they had the rights to Nintendo's Donkey Kong character. They are responsible for bringing him back into his first starring role since Donkey Kong 3 in his own adventure - Donkey Kong Country. Therefore, Rare are to thank for the Donkey Kong Universe as it is known today, with characters such as Diddy Kong and the Kremlings. Nintendo now owns the rights to all characters in the Donkey Kong Universe, but lost the rights to the characters in the Banjo and Conker Universes.