Omega

E-123 Omega is a character from the Sonic the Hedgehog series created by Dr. Eggman to contain Shadow the Hedgehog. He appeared in Sonic Heroes where he, Shadow, and Rouge teamed up to form Team Dark.

Super Smash Bros. Brawl
In Super Smash Bros. Brawl, E-123 Omega appears as one of the stickers that does +17 resistance.

Mario & Sonic at the Olympic Winter Games
E-123 Omega appears in Mario & Sonic at the Olympic Winter Games as the second rival of the festival mode. He races the player in Speed Skating and has rocket boosters that speed him up drastically. In team festival mode he is not the boss of speed skating and is instead the boss of the Short Track Relay.

During the Adventure Tour in the DS version, Omega appears in Blizland where he challenges Mario and Sonic to beat him in Intense Short Track. After he is beaten, Omega will reveal to Mario or Sonic that the reason why he came to Blizland was to try to defeat Dr. Eggman, but Dr. Eggman would only accept his challenge if he defeated Mario and Sonic. When he leaves, Toad says he thought Omega would join them.

Trivia

 * Omega is the only rival in Mario & Sonic at the Olympic Winter Games to appear in two different locations. In Festival Single mode, he appears at the Olympic Oval while in Festival Team mode he appears in Pacific Coliseum.