He was created by Shekhar Subramanium, and is clearly more powerful than G.One, his enemy and the hero of the film. This was because Shekhar tried to satisfy his son Prateek, who liked Villains more than Heroes.
He is very evil and villainous, having powerful electric powers as well as Shape-Shifting. His goal was to kill Lucifer (Prateek Subramanium), after Aakaashi was killed by Ra.One. He also killed his creator Shekhar as well as Aakaashi's mom in cold blood.
His main theme colour is Red. Ra.One has several real appearances. Ra.One's first avatar was Aakaashi, Shekhar's Chinese colleague who was his first kill His second one appears to be a bald normal tattooed man donning a Super-Suit, and has a lot of Tattoos on his back and his neck. His third and fourth appearances are Sonia and a faceless skull-faced monster.