E-117 Sigma

E-117 Sigma was an E-100 Series robot.

History
Sigma was the eighteenth E-Series robot created by Dr. Eggman. At some point E-102 Gamma tracked it to Old Megaopolis in Northamer. During the battle Gamma was infected with Zero Viruses, causing him to receive multiple liberation confirmations, but it continued its pursuit of Sigma regardless and destroyed it, freeing its Mobini. (ASUB)

Background Information

 * Sigma was never formally introduced in the comics, but his fate was revealed in the (now defunct) Sonic Universe blogs.
 * Sigma's Zero Viruses are a reference to the Mega Man series, which are connected to another character named Sigma.