Bellicus is Alien X's voice of rage and aggression.
Bellicus looks like a male green human face with very realistic features (i.e. the wrinkles on his face).
When Ben transformed into Alien X for the first time, and Ben quickly discovered he was locked inside the form because of the eternal debates between the two entities who control its body, Serena and Bellicus. He is then forced by Ben to do what he says, as they find Ben has a weapon against them. Professor Paradox is not allowed to be closer than 500 light years to him and Serena, or any Celestialsapien for that matter.
- Reality Warping