E-123 Omega is a robot that was created by Dr. Eggman to guard Shadow the Hedgehog when he was in stasis, leaving Omega in storage with Shadow. This prompted Omega to rebel against Dr. Eggman. Initially a minor character in Super Smash Bros. Crossover, Omega becomes a more important character in Season 23, where he starts actively helping the heroes, determined to get to Dr. Eggman so he can exact vengeance on him for abandoning him. Omega is also responsible for helping Shadow return to life, as he inserted the microchip with Shadow's memories into a Shadow Android, and managed to convince E-102 Gamma to rebel against Dr. Eggman. In Season 32, Omega sees Sonic the Hedgehog return to HQ after he had left the Heroes of Legend. Noticing Sonic's depression, Omega asks why he isn't on Final Destination, and learns that Sonic abandoned the Heroes of Legend and of the situation with Knuckles the Echidna. Trying to comfort Sonic despite not being able to comprehend emotions, Omega states that when something or someone becomes too powerful, it is eventually seen as a threat, and then the world becomes its enemy. Omega then states the worst is about to come, and that the Heroes of Legend need Sonic. Omega reminds Sonic of all his past accomplishments, and how he didn't give up after Sally was killed. Omega ultimately manages to restore Sonic's fighting spirit and confidence. In Season 34, although he is immune to the Midna Virus, Omega is reprogrammed by Mecha Sally along with Gamma and R.O.B., and becomes a member of Mecha Sally's growing army.
- Despite his hatred of Dr. Eggman, Omega only wants to kill Modern Eggman, since Omega knows that he won't exist if he kills Classic Eggman.
- Compared to the Sonic games, Omega has a lot more interaction with Sonic and his friends.