The E-Series (Ｅ－シリーズ E - shirīzu?) are a robot line that appears in the Sonic the Hedgehog series. They are a production line of robots created by Dr. Eggman, who uses them in his quest to conquer the world. They are considered to be elite versions of the Badnik robots Eggman used in earlier games. The name was first used in Sonic Adventure. The most famous E-Series robots are the E-100 Series from Sonic Adventure, particularly E-102 Gamma (who was a playable character in that game) and E-123 Omega (who has been a recurring character since his introduction in Sonic Heroes).