Team Dark is one of the 4 teams from Sonic Heroes, alongside Team Sonic (their rivals), Team Rose, Team Chaotix. Its members are Shadow the Hedgehog (speed type), Rouge the Bat (flight type) and E-123 Omega (power type), with Rouge being the de-facto leader throughout Sonic Heroes and Sonic Free Riders, Shadow taking the lead in Sonic the Hedgehog.
Team Dark made their appearance in Sonic Heroes. The treasure hunter and their Rouge hears of a secret treasure in one of Doctor Eggman's base. Upon entering, she instead finds Shadow in a stasis pod. After freeing him, she unknowingly activates Omega, the last of the E-100 line of robots, and it isn't until he opens fire that he makes his presence known. Rouge is able to stop Omega before anything serious happens. She learns the whole story from both: Omega is mad at the Doctor for sealing him, and Shadow has lost his memories. Rouge decides that they team up, seeing that their problems point to Eggman, Team Dark also fought against Team Chaotix (due to disgust at being mistaken for Eggman's henchmen, as well as their potentially being rivals for Rouge's hunt for Eggman's treasure) and Team Sonic (simply due to their being in the way of locating Eggman).
Sonic Free Riders
Only two of Team Dark's main members, Shadow and Rouge, appeared in Sonic Free Riders, participating in Dr. Eggman second World Grand Prix, apparently just to get the cash prize and treasure. After discovering that a third member of there is a requirement in order to participate, Rouge conveniently finds a robot called E-10000B who acts as the power member of the group. On several occasions, E-10000B pleads at Shadow and Rouge to get some rest but the two denied it. Eventually, just when Team Dark is able to win against Team Rose, E-10000B finally is busted and is escorted away for repairs while Shadow and Rouge take on Team Rose themselves.
At the end of the story, it is revealed that E-10000B is in fact Metal Sonic in disguise, who joined the team in order to copy other character's abilities to make himself strong enough to challenge Sonic in a race.
Appearances in Other Media
Team Dark finally appeared in the Archie continuity in Sonic Universe's fourth issue. They were sent to the Special Zone by G.U.N. to retrieve a Chaos Emerald. The team was later seen in Sonic's Universe's 5th arc, Treasure Team Tango pursing a Sol Emerald with Blaze, Amy and Cream.