So...more questions.
I've realized that in the Dreamscape, the inscription in the southern cavern says it's the beginning of the Dreamscape. It could be put there by Darkrai itself, but telling the reader "We are lucid" and "Help us" or "Heal us" seems a bit strange if so. Could it be connected to the mirror Waldenhall destroys, i.e., an equivalent in the Dreamscape of sorts? After all, at the end of E6, Reeve does say that perfection will spread like a plague, and that's how Aurora explains the Dreamscape (which also seems to line up with what the inscription says).
The other confusing thing is the lake trio being there. I believe the game tells us that the lake trio was there before the Dreamscape came to be, which would imply this is just another plane, one Darkrai was confined to when it didn't reach perfection, rather than a plane created by Darkrai itself.
Which also brings us to the point made by Shiv in the East Cellia sewers, when he says that Darkrai was (trapped) in the Dreamscape during its infancy. So...maybe the events at the very beginning (intro) of the game, whatever happened there, made Darkrai be reborn or something? Maybe, like Kuiki, it got stuck in a plane where time was accelerated, but backwards. It seems odd but there has to be an explanation for Darkrai to have reached perfection, even if only for a moment, and then be in its infancy in the Dreamscape.
Also, I wonder why the player is the one that can release Darkrai and not another character like Nova and the twins. Paired with what Reeve says about the player not showing the expected decay from having interacted with a perfection fragment, it really makes it seem like the player is superior to these three.
Another thing that intrigues me is the fact the voice (Darkrai's trainer) keeps comparing Waldenhall and the player, as if they were equal. If these interactions had only happened after Fairbale I would say its due to the interaction with the perfection fragment, but the trainer keeps interacting with the player way before that, which means the two are connected somehow. At one point, the player can hear that they are "two bodies in the same grave". But, whose grave? Is it Darkrai's trainer's grave? If so, it would make sense that the trainer mentions the player is an empty shell.
I'd also like to point out that Darkrai's trainer apparent "true form" in the mirror seems rather...rotten? Like, Reeve says that the trainer ascended to perfection without its trainer, but the trainer itself seems to just be like a shadow. In the intro, we seem to read a scream of pain of sorts, so what if not only is that trainer trapped, but also rotting? Perhaps that's why the Dreamscape started spreading and why Darkrai was confined to that specific plane?
Also, what's with Weeping Hill? Like Vejyr, it has a Sanctum, but with the grave of Keegan no less (what's the meaning of this?), and iirc it's only accessible after Shiv creates an entrance to that room. It'd be weird for Shiv to create an illusion that makes Keegan stand out considering how much he seemed to hate him. But what also buggers me is the fact that you get the Onyx Stone from Shiv's memory, which would mean you get it...out of his head??? Which in itself implies Shiv can just invite people into his mind, and then take stuff out of it into the real world. But back to the Onyx Stone, if it's obtained from a memory (rather than the real one, with an unknown location), then how come it has the same power as the real, past one?