Team Dark is a trio consisting of Shadow the Hedgehog, Rouge the Bat and E-123 Omega, all of who joined forces to track down their common targets, occasionally working for G.U.N. or with Sonic and his allies, helping to protect the world whenever a threat occurs. Consisting of highly powerful and fearsome individuals in their own right, Team Dark is a force to be reckoned with and often appears to content with some of the world's greatest threats and champions.

Omega, is a badnik created by Dr. Eggman as the last and most powerful of the doctor's E-Series robots, only to be deactivated and sealed in an abandoned base to guard Shadow the Hedgehog who was in suspended animation in a stasis capsule. Furious at having his power wasted in this way, Omega swore revenge on Eggman. Rouge the Bat then accidentally reactivated Omega when trying to free Shadow and she soon convinced the two of them to join together as Team Dark to track down their mutual enemy. Continues to pursue his mission, occasionally coming to the aid of his allies. Omega's only goals in life are to take revenge on Eggman for wasting his potential and destroy the doctor's other robots to prove himself superior. As a result, he tends to be extremely headstrong and reckless, unlike his teammates on Team Dark. Omega's upper body and arms are stocky; his eyes are red. He is large with a visible Greek symbol on the front of the left and back of the right with red handlebars on the top.

Chaos energy, also known as Emerald forces and Chaos Emerald energy, is an unstable, yet powerful mystical energy that each Chaos Emerald and the Master Emerald generates by turning thoughts into power. This energy can be used for super transformation, to perform Chaos Control and various other chaos powers, or as a power source for machines. This power can be controlled by the Master Emerald, if requested or commanded by its guardian.

The Guardian Units of Nations, often abbreviated as GUN or G.U.N., is a worldwide military and law enforcement organization. Run by a man only known as the Commander, G.U.N. seeks to protect the earth from all sorts of threats, including Dr. Eggman. G.U.N. possesses vast resources, including an army of soldiers and peacekeepers, fighter planes and other instruments of warfare. While G.U.N. receives orders from the President of the United Federation, it operates under the sole discretion of the Commander, who is known to use G.U.N.'s resources to bring down enemies.

Sonic is a blue-furred anthropomorphic hedgehog with green eyes and peach muzzle. He wears white gloves and red sneakers. Born with the ability to run faster than the speed of sound, hence his name, Sonic possesses lightning-fast reflexes to match. As his species implies, Sonic can also roll up into a concussive ball, primarily to attack enemies. Well-known for his legendary cocky attitude, easy-going demeanor, and somewhat short temper, yet strong sense of justice, compassion, and love for freedom and adventure, Sonic uses his abilities to protect the innocent from his world and those beyond from the forces of evil, especially his arch-nemesis, Dr. Eggman.

Doctor Eggman is a human scientist and the arch-nemesis of Sonic the Hedgehog. This large scientist with an IQ of 300 dreams of dominating the world, but his constant plots to create his Eggman Empire were always thwarted by Sonic and his friends. While all these plans end in failure thanks to the continued efforts of Sonic and his friends, the mad doctor is somehow always able to slip away from certain death or imprisonment and escape at the last moment, making him a constant threat to the universe and a thorn in Sonic's side as well as G.U.N.'s. Eggman is a short-tempered, raucous, pompous, and cruel evil genius. Rotund in appearance, Eggman possesses a bald head, a bright red nose, and a very bushy mahogany moustache. He wears both his tinted glasses and green-lensed goggles as headwear and elegant red coat.

Shadow is an anthropomorphic black-furred hedgehog/alien hybrid with red eyes, white chest fur and tan muzzle. He wers white gloves, air shoes and Inhibitor Rings on his wrists and ankles. Shadow was created as the immortal and ageless "Ultimate Life Form". He's the arch-rival of Sonic. Shadow is sharp-witted, always on edge, and possesses a strong sense of purpose, willing to accomplish his goals by any means. Shadow can match Sonic in both speed and skill, and can use Chaos Control with a Chaos Emerald. While preferring to work alone, he helped Sonic and his allies when needed. Shadow is a member of Team Dark.

Hedgehogs are anthropomorphic animals covered in fur and quills and possessing small tails. Features they share include large heads, short fur on most of their bodies (excluding certain areas that differ between each individual) which is frequently bright-colored, short muzzles, and spiky quills on their heads of varying styles, similar to hairstyles. Male hedgehogs possess masculine figures and female hedgehogs are with more feminine curves. Hedgehogs often possess special abilities such as speed and enhanced strength. They also can curl into a ball and use ricochets to bounce around objects. Their average height is 3 feet.

Chaos Control is a chaos power ability that allows the user to manipulate or warp the fabric of space and time using a Chaos Emerald's chaos energy, and its effects can be molded into affecting reality in a multitude of manners. The power of Chaos Control is enhanced with each Chaos Emerald added to its usage, until reaching full power with all seven, meaning that the more Chaos Emeralds that are used in the process, the greater is the extent that the user can warp space and time. Chaos Control requires at least one Chaos Emerald nearby to draw power from.

The Chaos Emeralds are seven ancient emeralds and mystical relics tied to the Master Emerald that possess powerful properties and abilities. Those that hold the Chaos Emeralds can use them for a variety of things, such as warping time and space, powering machines, and initiating Super transformations. Anyone who combines all seven Chaos Emeralds can control unimaginable power. Even when not including their mystical powers, the Chaos Emeralds' monetary value and beauty make them prime targets of treasure hunters who seek to make a mint.

Badniks, also known as Eggman's robots, are robots created by Dr. Eggman. They are used by Eggman as his private robot army, being the major part of the Eggman Army. Currently, it appears that Eggman is getting away from the personalized, ornate designs of his original machine lines and is moving for a more mass-producible line of machines. Their strength lies in numbers and their leaders, such as Dr. Eggman himself. Omega hates badniks despite him being one of them.

Rouge is a white-furred anthropomorphic bat with teal eyes, big ears, sharp fangs, purple wings, and curvy figure. As a spy, Rouge is trained in combat, stealth and infiltration, and possesses both super-level kicking power and flight. Rouge is in short, an enigma, as her motivations are always in question. In truth, she is usually just out for herself. She is smart, sassy, and seductive, and knows how to get what she wants. Once there's a target in her mind, she always goes for it, regardless of the costs. Beneath her ditsy exterior though, she is a calculating realist and her motives are always mercenary in nature. Regardless, she is loyal to her closest friends. Rouge is the leader of Team Dark.