>>721110353
If it was her avatar that she used against Fibrizo, then sure. The novels have it so that destroying him exhausted the avatar's power and manifestation. But the full self of the LoN created all of the staves containing all of the worlds of Slayers, unknowingly at that. It's as far beyond the Mao as the Mao are beyond any other demon.
As for the chart - given it's meant to parallel the Kabbalah, it's not so much a sign of their power as it is saying that each of the demon kings represents an aspect of the LoN's totality. The Son's position at the top is meant to evoke Keter/Thaumiel, the Crown of the Sephirot/Qlipoth and highest emanation of God.