Faerie and the Long Earth

There are nigh-infinite iterations of the world, spread out across the multiverse like pearls sewn into lace. Not all of them are real, though.

Reality and Unreality
'Realness' is a property of the universe, like time or matter. Some things are real (like dragons), some are unreal (like illusions or gremlins), and most things fall somewhere in the middle (humans are about 80% real).

Unreal things can have all the other properties, such as mass, inertia, shape, although frequently they are lacking one or more of those things (Real things must have ALL the properties of Realness, while Unreal things are less fettered). But they are unstable, they flicker, warp, and dissolve. Few unreal things last more than a day, more often they pop as soon as they would undergo a change, since there is nothing to anchor their existence through such an experience.

Every time you flip a coin, turn left instead of right, you create another iteration of the universe where the other outcome occurred. But none of those are real. There is only finite energy, finite information to 'render' and maintain all of the unused versions of a path. All around the central causality, the world we all experience, there are soap-bubble like fragments of probability; jam-packed and nearly solid near the centre, and then spreading out into misty shards as you get into less plausible 'what-ifs'. The Material Worlds hurtle through non-existence, pulling the possible into being, dragging the improbable in their wake like smoke, before discarding the impossible back into the void.

But all those little scraps of unreality have to go somewhere.

Overmorrow & Ereyester
You can walk out into the shoals and sandbars of realness, wander through the might-bes and might-have-beens. Soothsaying techniques use this to a limited extent, looking out across this archipelago by flattening out a map sketched in guts or bones or runes or cards. But with the right twist of magic, you can step out of This Place, and into one of the side corridors. You can even go there physically, unlike the purely psychological landscape of the Dreaming. You might not even notice when you step over the border.

The near places are very similar to your own. You can see what might have happened if you'd made a different choice. You can peek into the room ahead of you, to see what lurks there. You can bring a little bit of that timeline back with you, with the right magic, for a little. As you get further away, specific iterations get harder to find. The bubble-realities further out start to warp and get weird, merge into each other and dissolve.

If you go far enough, by the right roads, you might step off the islands and into another kingdom. The land of Overmorrow lies in the future, east of the sun. Ereyester lies in the past, west of the moon. These are lands apart, gathered up from the fragments of cast off timelines, like the shell of a caddisfly nymph

Over the eons, peoples have settled these timelost realms, fleeing into unreality when their own worlds fell into shadow. These are the Elves, Gnomes, and other Fey folk- as well as the Raksha, the true fae, who are children of Unreality itself, and the destroyed world they fled the nonexistent one.

Not all realms have peoples wise enough to know the Ways, hidden behind mirrors and across streams, and not all who can find the Ways survive their wanderings. But of those who do, many make the journey across the Long Earth, and find their way to the realms of Annwn.

The Abyss
Throughout the eons, the legions of demons, voracious monsters who gnaw on the fabric of reality, have boiled out of their dimensions and destroyed world after world. Scholars believe there were once thousands, perhaps millions, but now there are only five- and of those, two are unreality-scoured wastelands. Perhaps there are more, but they are lost in the mists.

The Abyss, once crafted as a prison, constantly grows by the hunger of these monsters, pushing ever outward, chipping at the roof of hell.



The Long Earth
Between the five known Material worlds lies a path. A twisting and changing chain, but one that can
be walked by those with the right skill. Called the Green by some, for all of these mayfly worlds have never seen the axe or the sickle. While the worlds come and go, the trees seem to have a wisdom and a Reality all of their own, persisting between iterations, growing strong alongside the path the runs through the Great Forest between worlds. It is along these ways that the elves first walked, when they made their way to Annwn.

the Dreaming
There is only one Dreaming. All the little realities connect to it. There might be a million, a billion iterations of you, but you only ever have one dream. Why do you think it sometimes seems like, when you dream, your memories of your waking life seem to belong to somebody else?