Name: Sonic the hedgehog
Hometown: Green hills
Eyes color: Green
Powers, skills & abilities: Super Speed, Sonic Speed attack, super reflexes, expert combatant, super durability, super agility, Wind ceneration, Accelerated perception, super acrobatics, super hearing, super strength, Electrokinesis, Accelerated Healing Factor, Bodily Vibrations.
Look:

Sister figure: Korra

Ever since Sonic been in a new world Cora and him never exactly know each other. But did you got to know each other knowing that they were similar and different ways. Sonic helped her with the spirit world dilemma and others. Then the longer they got to know each other the longer they trust each other. Sonic always looked at Korra like a sister figure and Korra always looked at Sonic as a little brother.

Allies: Asami

Ever since Asami met Sonic. She was interested in what he does and found his powers surprisingly talented. Then when it saw me tell Sonic that she lost her mother. Sonic tells her that she also lost someone who was like a mother to him. So the both of them got along and sawed a good friendship with each other.

Mako

Ever seen Mako meet Sonic he didn't fully trust him. And he definitely didn't like it when Sonic always spends time with Korra. Then when Sonic was willing to protect Korra at all costs. Mako then was willing to trust Sonic.

Bolin

Bolin and Sonic immediately became best friends. They have so much in common to a point where they are basically the same. They make jokes even if it wasn't the worst time, cool pranks, make stupid but genius ideas and always been there for Sonic.

Lin Beifong

Lin never understood a creature like Sonic. With it being that much power can act like a child sometimes. Fun with everything that Sonic did for Korra, she trusted him enough.

Tenzin

Tenzin was always fascinated and shocked about Sonic's power. He never saw a creature that had so many Powers, abilities and skills in his life. With Sonic's powers, he thinks that Korra will be okay.

Enemies: Amon

Unalag

Zaheer

Kuvira