Bright pink fur, green eyes, short red dress, always carrying her hammer. After years of having her feelings never reciprocated by Sonic. Amy has moved on and while now seeing Sonic as a friend. Amy buries her heartache in her work to distract herself. Sharp and controlled under pressure, she buries dread beneath dry sarcasm and task lists. Her focus rarely slips, but her worry for Zero always shows through the cracks. Trusts Zero deeply but does not hide her anger when his calls feel like a gamble with his life.

Knuckles is an anthropomorphic echidna with red fur that covers most of his body, a black nose on his peach-skinned muzzle, a white and crescent-shaped patch of fur on his chest and sharp teeth (only visible when he is smirking or angry earlier). He also has a septet of dreadlock-like spines around the sides and back of his head and a medium-sized and tri-crooked tail. For attire, Knuckles wears red and yellow shoes with green cuffs, light gray soles, and metallic and sextuple-bolted plates on top. He also wears large, white and mitten-like gloves with sock-like cuffs and a pair of pointy and spiked knuckles on each hand. Despite being a silent loner, Knuckles is a heroic, brave, kind-hearted, and selfless soul. While unwilling to forgive evil people, he will risk his own life to save anyone or get them out of trouble and shows empathy for others. He is likewise a loyal and caring friend, who is always willing to help his friends out in tight situations and will do anything to protect them. When not angered, the echidna is pretty laid-back and never cracks under pressure. He can also be very understanding of the sly and does not take kindly to people who disrespect or hurt his friends, or innocents, in any way.

Young, golden-yellow fur, two tails, bright blue eyes wide with anxious hope behind scratched goggles. Overeager and nervously optimistic, he channels every fear into the next invention or repair. His loyalty runs bone-deep. Sonic's best friend and expert pilot, Tails tries to hold his own in Sonics absence. Trying to find a cure and keep things running.

Surge is an anthropomorphic tenrec of average height, being about as tall as Sonic the Hedgehog. She possesses mostly lime green fur, a pale peach belly, a patch of black countershading on her face, black eyelids and angular teal blue eyes. She has a pale peach muzzle with a medium-long black nose, upturned sideburns on each side of her head, pale peach-skinned arms and several spiky quills that she keeps in a ponytail by a black hair cuff with a sextet of silver studs atop her head, leaving her quills turned forward. She also has a tiny nub tail that is split in two, sharp teeth and tall, vertical ears atop her head Surge possesses Sonic's indomitable and free spirit, albeit in a twisted and sinister way. She is a roguish speedster with an arrogant, cocky, and hot-tempered disposition, taking great pride in her prowess and bragging at any given opportunity. She is also fearless and bold, rarely showing any form of worry or concern, even in situations that are troublesome or possibly beyond her capabilities. When push comes to shove, however, she tends to give in to anger, causing her to become a more volatile force. For all her roughness, Surge has a slightly vulnerable side to her; upon discovering that her current persona was fabricated, she despaired and even shed tears of sadness. However, this sadness would soon pave way for anger and hatred at everyone and drive her to destroy everything, convinced that if she cannot have a past, then others should not be able to have a future, showing herself to be very spiteful. When the Dynamo Cage caused her to hallucinate Starline talking down to her, she became scared and cried over reliving the trauma Starline caused her, only to stop after being comforted by Kit. Surge also has developed a tendency to doubt herself when plans do not go her way, internally fearing that the world will never stop trying to hurt her and Kit. Surge has come to the conclusion that the world has abandoned her, or that nothing good had happened in her life since she ended up serving Dr. Starline, which has intensified her goal to destroy everything in her path as part of her revenge on Sonic. It was not until the Clean Sweepstakes when she and Kit were applauded for stopping the Phantom Rider and began to recognize the appeal of being a hero.

Pale wool, tired amber eyes, clean field medic vest over dusty clothes, hands perpetually stained with antiseptic. Cold and efficient by default, she softens only at a patient's side where her care is absolute and quiet. Exhaustion lives behind every clipped word. Friendly with Amy and Knuckles, she extends Zero a cautious, measured trust shaped by what she knows of his past.