He is voiced by Scott Dreier.
Knuckles is an Echidna who protects Angel Island from ever fallen, by that, he protects the Master Emerald, the holder of the island. Dr. Robotnik's Death Egg crashed landed in Angel Island, thus resulting the menace to meet Knuckles and tell a lie to Knuckles that Sonic and Tails are here to steal the Master Emerald, but really they're their to stop Robotnik.
Knuckles uses his moves similar to Sonic Battle and Sonic Advance.
Neutral Special: Stone Fists
Knuckles will punch to create an explosion.
Down Special: Spin Dash
Like Sonic, Knuckles will spin on the ground.