Marilyn Manson's music, mainly Holy Wood, Antichrist Superstar, and Mechanical Animals, is one big well-planned metaphor.
Omega is the persona that "Adam," Marilyn Manson, took on when his transformation was complete. Omega means "the end." Omega is this hollow rock star, becoming a "mechanical animal" in the end.
A mechanical animal being the people who depend on drugs, sex, TV, etc. for a fake happiness.
Coma White is a fictional representation of a girl who is the image of perfection, MM's love interest. At the end of Mechanical Animals, he realizes that Coma White doesn't exist, what he had been striving for is a lie.
Also take a look at Coma Black. It ties into the idea of Coma White as well.
Okay, here we go...
Marilyn Manson's music, mainly Holy Wood, Antichrist Superstar, and Mechanical Animals, is one big well-planned metaphor.