The Vanu are the ancient aliens that lived on Auraxis, and are the beings that the Vanu Sovereignty based their weapons and beliefs on. It's unknown what happened to the Vanu, but the Vanu Sovereignty believes that they reached a new form of existence. That could explain why there is no flora or fauna on Auraxis. Their appearance is also unknown and the only person ever to hear them was Henry Briggs when he discovered the second figure 10 years before he committed suicide.