E-123 (Ｅ－１２３ Ī Wan-Tsū-Surī?), codenamed Ω or Omega (オメガ Omega?), is a character that appears in the Sonic the Hedgehog series. He is a robot created by Dr. Eggman as the last and most powerful of the doctor's E-100 Series line of robots. However, he was 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 his creator. 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.[6] Although Omega failed to achieve his goal at the end of his team's adventure, he has continued to pursue his mission, occasionally coming to the aid of his allies and other heroes.