Omega is a former servant of Eggman, and the most powerful in the E-100 series. Switching sides after a programming anomaly, Omega is a deadly enemy of Eggman (more that than an ally to anyone else) who gets his kicks from using excessive force whenever it’s viable to do so.

Omega might be a robot but in the comics he has a very distinct personality. You may use a monotone if you wish but it is not necessary, and regardless of the tone the flow of the syllables should sound natural. Keep the voice medium as you speak, though.