They are separate entities, who have both appeared at the same time and talked to each other. Vena is more aggressive and cunning, while Vatz is more passive and timid. It is still possible the are working toward a common goal, or they really could be twin races that are fighting like they originally said. That is one of the big remaining questions of the series.Clearly both of the mascots are working together, They look unreasonably suspiciously similar. They're practically the same being. The best way for this to play out is Vena is just playing both sides of the field to harvest the most energy.