upon further thought… i think it is possible that the time prophets ‘uncertain moon’ could exist in both universes. it could be like the theatre in “Brigadoom” in which the Master of Ceremonies says that “they live outside of time and space”. he also stated that when the universe ended that they would go on.
The Time Prophet definitely exists in the Light Universe, since HDS visited her, and the Dark Zone is beyond his reach. She may or may not also exist in the Dark Zone. The Brunnen G on Brunnis visited her, but its possible they crossed over to do so.
One possibility I’ve pondered: What if the Time Prophet’s “uncertain moon” lies on an orbital path that takes it back and forth THROUGH the Fractal Core?