E-121 Phi

E-121 Phi is an Emerl-based robot made by Dr. Eggman. Dr. Eggman took Emerl's data and copied it as stated in Rouge's story mode. The Phi robots are powered by Chaos Emerald Shards, rather than whole Chaos Emeralds.

The only physical difference between Phi and Emerl is Phi's grey hue and brown eyes, as opposed to Emerl's yellow and blue. The Phi's ability to copy attacks is identical to that of Emerl, but since the ability is only powered by Chaos Emerald Shards, as a whole it is weaker than Emerl's. They are about as intelligent as Emerl was when he had two Chaos Emeralds, and generally just repeat one word while speaking, such as "Located! Located!".

Oddly enough, Phi is numbered as E-121, meaning he was created before E-123 Omega. However, Sonic Battle takes place after Sonic Heroes, where Omega was introduced, as Rouge comments on Gamma and Omega looking similar. Why Eggman didn't use Phi until Sonic Battle is unknown.