A war machine built by Dr. Weil specifically to destroy all of humanity, and has single-handedly wiped a large proportion of the human race.
Omega is a megalomaniacal monster who possesses a god complex, one of which where he sees himself as a perfect hero, and is completely obedient towards Dr. Weil, doubtlessly believing his purpose to destroy mankind.
He possesses the original body of zero, essentially turning him back into the monster Dr. Wily intended for him 200 years ago.