Characteristics
According to various official materials from Sega, Sonic is described as a character who is "like the wind": a drifter who lives as he wants, and makes life a series of events and adventures. Sonic hates oppression and staunchly defends freedom. Although he is mostly easy-going he has a short temper and is often impatient with slower things. Sonic is a habitual daredevil hedgehog who is honest, loyal to friends, keeps his promises, and dislikes tears. He took the young Tails under his wing like a little brother, and is uninterested in marital proposals from Amy Rose. In times of crisis, he focuses intensely on the challenge as if his personality had undergone an astonishing change.
Sonic is known as the world's fastest hedgehog. Sonic's greatest strength is his running speed, which is faster than the speed of sound. Many of his abilities are variations on the tendency for hedgehogs to roll into tight balls for protection with the addition of spinning his body. Since his introduction in 1991's Sonic the Hedgehog, Sonic's primary offensive maneuver is the basic "Spin Attack" (or "Sonic Spin Attack"). Later games in the series expanded on this basic attack and two of these enhancements have become mainstays of his: the Spin Dash which was introduced in Sonic the Hedgehog 2 and involves Sonic spinning on the spot before blasting off at full speed, and the Homing Attack, officially introduced in Sonic Adventure, in which Sonic dashes toward a target in mid air. Sonic's only weakness is that he cannot swim, sinking like a rock if plunged to a deep body of water. However, he can overcome this by running on the surface of water.
When the seven Chaos Emeralds are collected in most Sonic games, Sonic can initiate a Super transformation into Super Sonic, a faster and invulnerable version of himself that can fly. He can normally transform into Super Sonic with 50 Rings. While transformed, Sonic slowly loses Rings during the time he is in Super form (usually about one every second) and returns to normal when all the Rings are used up, usually incurring the loss of a life during a boss; the player can collect more Rings during this time to maintain Super form.
Read more about this topic: Sonic The Hedgehog (character)