Sonic the Hedgehog is the fifteen year old main character of most Sonic games, and is also the most popular character of each character. He has also had a rivalry with the Nintendo Character, Mario, back in the late 90s. His popularity started when SEGA made Sonic the new mascot, replacing Alex Kidd. Sonic's original name, was also Mr. Needlemouse, which soon became a Sonic the Hedgehog rom hack. Fans also think of "Blast Processing" based on Sonic the Hedgehog himself.Sonic has super speed, reaching the speed of sound. He also has a few other abilities, like the Sonic Wind, the Spin Jump, the Sonic Boost, the Homing Attack, and the most famous of all of his abilities, the Super Spindash, introduced in Sonic the Hedgehog 2. Another famous ability introduced in Sonic the Hedgehog 2 is his Super Form. By gathering all seven Chaos Emeralds, his Super form grants him the ability to run faster then the speed of light, and the ability to become invincible to every single enemy. He can still drown, and get crushed by enemies, however. He also needs fifty rings to activate his form. Sonic also has a few rivals. His first, is Knuckles the Echidna.
Sonic is the most well known Sonic character because he's starred in every single Sonic game, (not counting spinoffs like Knuckles Chaotix) starting with Sonic the Hedgehog (game). He has appeared in comic books, television shows, japanese doujinshi, and even a movie. In the comics, Sonic has a girlfriend, named Sally Acorn.
Sonic is a very impatient character, but is always willing to help out whenever needed. He also has a best friend, named Miles "Tails" Prower. Tails has helped Sonic since Sonic the Hedgehog 2. His impatience shows in the games, when he taps his foot whenever you don't move the character (Sonic the Hedgehog, obviously) around. In Sonic CD, however, whenever you don't move him for three minutes, he'll jump off the screen, making your game have a game over.
Sonic has gotten most of the feedback positive, but also has gotten bad feedback, ever since Sonic the Hedgehog 06 was made. Sonic is concidered one of the best video game characters, and possibly will always will, since his games, new or old, are always being replayed.