Chaos was the original Valheru, spawned forth from the very essence of the Void itself. Every Valheru after that was spawned from Chaos� likeness which he spread to his children, which spread it to their children. Only Chaos could truly draw his energy from the Void, but this energy constantly flows through him and into his children, like a sort of output. Therefore in explanation, all Valheru draw their powers from the Void, but it comes through Chaos to them.
(i.e.: the Void is the TV station, Chaos the Satellite, and all other Valheru the TVs, the signal only goes one way, you don't send messages from your TV to the station!)
This does not cause Chaos any loss in power, it is simply the Flow at which the energy travels. Now if a Valheru was to assault Chaos with Energies, this would upset the flow, and actually stop it, causing that Valheru to lose its connection with the Void, and if for an extended amount of time that Valheru would not only remain powerless, but Valheru life depends on the Voids essence, without it, the Valheru would die.