E-106 Eta

E-106 Eta is a E-100 Series robot.

History (Pre-Super Genesis Wave)
Eta was the seventh E-Series robot created by Dr. Eggman. At some point it was stationed in West Robotropolis, but it was tracked down by E-102 Gamma and its Mobini battery freed in the process. (ASUB)

History (Post-Super Genesis Wave)
After Sonic's world was re-written by the Super Genesis Wave, Theta was resurrected as a Badnik Horde commander, though his name remained the same akin his previous life - his number was changed to E-107, and he was the leader of a Badnik unit stationed around Spagonia. Eta and his unit kidnapped Professor Pickle and Dr. Chuck the Hedgehog under the orders from Eggman and took them and their research back to the doctor.

Background Information

 * Eta was never formally introduced in the comics, but his fate was revealed in the (now defunct) Sonic Universe blogs.
 * Originally E-107 Theta was intended to be the main villain of StH #258. However, due to Theta's connection with Light Mobius his role will instead filled by Eta, according to Ian Flynn.