Something I was thinking about is what if Madame X is Celine. What if the ritual that she had to before where the current team Xen headquarters is a ritual that splits herself in two. Where one side fights for truth and the other fights for ideals. The ritual is finished if done correctly with the two sides ending in a stalemate. But what if the ritual is failed, and one side wins. I do not remember which one of the stones either the white or black stone that Alexandra said the Celine brought back was, but this would explain why Madame X knows so many things and why her face is black and hair is black.
What if Celine is trying to set up both sides of the prophecy, the light and the dark prophecy to she which side wins out. She built the league to test the members of the light prophecy, and team Xen to unite the dark prophecy members. If the ritual scene that I described is how it went down then it would make sense if Madame X represents the truth, of that the dark prophecy will more likely happen. And then the other half of Celine representing the ideals, with the completion of the light prophecy being better for the world.