Next World? Lemuria!
Having read all the clues since defeating the Aethyr Titan, going through Karamelle, and now having seen what's on the other end of test realm, I think I've put together a picture of what the fourth story arc entails. And that includes going to the lost world of Lemuria as the next world. If you don't want spoilers, look away.
What is Lemuria?
Lemuria is what the Cabal made from stealing parts of other worlds. Their plan was to destroy the spiral and have it remade into some sort of paradise; but in order to weather that destruction, they didn't just need to build a ship to escape onto while Grandfather Spider sundered and re-wove the Spiral, they needed a pocket world to escape to until that job was done. The ship would lead them to that world, and that world was hidden outside the spiral. Thus was Lemuria born.
Why is the Nothing trying to get back to Lemuria?
The Nothing consumed the Old One at the beginning of Karamelle. This was sort of an accident on its part. It was creating void holes trying to pull the player wizard into its own world to confront it. But by grabbing and basically consuming the Old One, it integrated his memories and feelings into its own. The Old One was really trying to unite the schism of the Arcanum, and knew of Lemuria. Perhaps it was his idea of a promised place for the Cabal to retreat to and allow for a truce with the rest of the Spiral, or maybe a different offer of a constructed paradise. Maybe he was going to offer the rest of the Spiral a way to remake their worlds. But once the Nothing gobbled the Old One up, Lemuria began to die. The Old One is Lemuria's architect, its own pocket god, and without him to sustain it, it's dying. Perhaps because the Nothing has assumed some semblance of the Old One, that rate of decay has slowed; but he's not the real deal, and the part of the Nothing that is still the Old One wants the player wizard to save it.
What is the Nothing?
Piecing together what I know from the clues of the new quests, the Nothing is a being of pure thought born outside both the Spiral and from our own universe. It's own universe is a void. It IS its own universe, basically. But what brought it notice of the player wizard? I think that started when Ambrose pulled the player into the world of the Spiral. That imbued the player with an interdimensional specialness, so the player has a sort of energy signature to themself. And the battle with the Aethyr Titan, where the player united Shadow and Light into the Divine Paradox emitted a transdimensional beacon, alerting the Nothing. The Nothing saw the titanic battle from that signal, and so all it knew was elemental and spiritual violence. It's first contact with the player was thus in the form of battles with all the schools of magic.
The reason that other beings in the Spiral cannot detect the Nothing (except for the headaches characters mention when it's around) is that it's a transdimensional being where they are not. It operates on a different or higher plane of existence, and so does the player wizard. Sybil CAN detect it to a degree as well as Bartleby, as they are primal and attuned to the Spiral, with spiritual and dimensional roots that connect all the worlds in it. In Sybil's case, she is rooted between the worlds of the Spiral, touching just barely the edges and the outside of it. That is why she detects the Nothing clearer than even Bartleby. She felt the Nothing breach the Spiral, and she detects it's signature (maybe by the absence of the Spiral's essence that it leaves) when the Aethyr Titan is vanquished. She specifically summoned the player wizard, the only other transdimensional entity in this universe.
Is the Nothing a bad guy or good guy then?
I don't know. That may not be the right question. It's a reflection of what it experiences in the Spiral. It was a villain at first, because that's all it knew. Now, since it has absorbed the Old One, it is basically a ghost of the Old One. This is problematic in that the Old One was at least once antagonistic to the Spiral. If the Old One was on the up and up with trying to bring peace once again, that could mean the Nothing has learned something of redemption and goodness. There's still the problem that the Nothing isn't just the Old One; that's just one thing it's consumed. It still has the memory of the Aethyr Titan fight as well as the Aberrant Paradox fight. It still considers consuming an act of integration. I don't think that makes it evil, but it could make it inimical. If Lemuria is saved or otherwise dealt with, the Nothing might not yet feel appeased. Or it may find it loves the Spiral. So much that it wants to consume it!
Speculation on the end of the fourth arc
How can we know when we haven't seen the second world yet and all that happens there? I can make a hazy guess. This story so far is a journey of reflection. What does it mean to exist? What is the state of the universe? The multiverse? What gives a being or a world a right to exist, especially if that being or world exists at the expense of others? I think that things will go sour on Lemuria, and the Arcanum's schism may be renewed, but that journeying to another world for guidance will restore balance once again. Wallaru is where Zander and Jaki hail from, and they embody spirits of wisdom and wonder. Were the Nothing to eventually take something from Wallaru in the form of knowledge, it could perhaps find the peace that it's looking for. It may learn that you can enjoy a thing without having to eat it (own it). And that in turn teaches the player wizard something too.
This is what the fourth arc is about: a deeper understanding of life around us, and the echoes of our actions across what we know.
I wonder if we'll meet King Julien in Lemuria?
Addendum
A further clue of sorts. Going into the Reverie and completing the Dream Hive, the echo of Malistaire gives us some help to escape. He lets us know that we have the power to control our mind and focus on Mellori, to cast out with our minds and search for her. Isn't that the same thing that the entity we call the Nothing? Maybe having gone into the Reverie inadvertently broadcast the player's presence to the Nothing. "All minds touch here on the edge of the Other Side." Coming from Malistaire, without any other context, players might have assumed that this Other Side is the realm of Death or some sort of afterlife. But it is perhaps the other side of the Spiral's borders into parallel universes. If this echo of Malistaire is able reach across the void, since all minds meet (especially powerful ones), then this may have been the first moment that we signal our presence to the Nothing.
