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 2 action." "Sonic 2"s success was a major factor in Sega catching up to Nintendo in the early-1990s console wars. It brought their market share up to 40% within six months of its release. Tails, whom "Sonic the Hedgehog 2" introduced, went on to become one of the most prominent characters in the series, appearing as Sonic's sidekick in most "Sonic" media, including in recent games such as "Sonic Colors", "Sonic Generations", and "Sonic Lost World". "Sonic the Hedgehog 2"s popularity extended to various merchandise such as comic books such as "Sonic the Comic", a television series, and a sequel, "Sonic