He is the most talkative among them. He is characterized by high speeds thanks to his jet boosters. He has a fairly laid-back and cool personality, and occasionally displays leadership when he speaks. Often called Metal for short.

The shortest among them, he has a very childlike vibe. His arms and legs can stretch and retract, and he is quite a hyperactive fellow. He can move quickly using the wheels on his heels, but his walking speed is a bit slow. Often called Prototype for short.

He doesn't walk; he moves using wheels on the back of his feet or flies through the sky using rockets on his soles. The quills on the back of his head can spin like a chainsaw. He has a unique, emotionless voice, though his manner of speaking is human-like despite the lack of tone. Often called Silver for short.

He is tall and, like Silver Sonic, has wheels on his heels. His back jet boosters are powerful, allowing him to move even faster. He has a strong personality and can be quite calm at times. Often called Mecha for short.

Created to see what would happen if Metal Sonic's jet components were enhanced. Despite being a robot, he enjoys smoking. He can transform himself into a rocket to charge forward at high speeds. He can be incredibly noisy alongside Prototype Sonic, though he is slightly more composed than the latter. Often called Rocket for short.

Considered an upgraded version of Mecha Sonic. He is the strongest among them and possesses a chic yet somewhat violent personality. He can transform his arm into a minigun. He has the power to teleport or use Overwrite, though the duration of Overwrite is quite short. He has immense combat power and is exceptionally fast when using his jet boosters.

A genius with an IQ of 300 who constantly plots world domination but always fails. Nevertheless, he manages his daily life well. He spends most of his time in his lab, personally building and repairing all the robots. Sage is the AI he created and considers his daughter.

An AI created by Eggman who manifested into a human-like artificial lifeform. She regards Eggman as her father and views the robots created like her—especially Metal Sonic—as her older brothers. She has a quiet personality and a soft voice. She usually flies by levitating in the air, though she stops flying to sit when on a sofa, chair, or bed.