Knuckles the Echidna

Knuckles the Echidna is the tritagonist of Sonic the Hedgehog series. He is Sonic and Tails's best friend.

Sonic the Hedgehog
Knuckles and Sonic are close friends.

Miles "Tails" Prower
Tails is Knuckles' closest friend.

Amy Rose
Knuckles and Amy are close friends. He acts somewhat like an older brother to her.

Dr. Ivo "Eggman" Robotnik
Knuckles is constantly tricked by Eggman, due to his lies.

Rouge the Bat
Knuckles and Rouge have a love/hate relationship.

Storm the Albatross
Storm is Knuckles' arch-rival.