Sonic the Hedgehog protagonist Sonic the Hedgehog, a blue hedgehog able to run at supersonic speeds, and recurring villain Dr. Eggman, an evil scientist whose ambition is to conquer the world. Among Sonic's many allies, the most well-known include: Miles "Tails" Prower, a twin-tailed, highly intelligent yellow fox who is Sonic's sidekick and best friend; Amy Rose, a pink hedgehog who is Sonic's self-proclaimed girlfriend and a hero in her own right; Knuckles the Echidna, a coolheaded red echidna who is the guardian of the Master Emerald; Shadow the Hedgehog, an anti-heroic doppelgänger of Sonic with a dark past; and Metal Sonic, a
Sonic the Hedgehog of the Mario and Sonic crossover games. The first, "Mario & Sonic at the Olympic Games", was released in late 2007, and featured characters from both series competing in Olympic-themed mini-games. Its sequel, "Mario & Sonic at the Olympic Winter Games", was released in October 2009, and featured an emphasis on winter-based sports. "", a spin-off released in September 2008, was a turn-based role playing game developed by BioWare. During this timeframe, Sega took the franchise in a number of different directions. First was "Sonic the Hedgehog", which was released in November 2006 for the Xbox 360 and December 2006