The Metaphysics
Since the beginning of time, there had been multiple realities. Each was a self-contained "bubble", floating in the soup of primal forces from which it had emerged. Infinite realities. Infinite worlds. Each of these worlds had a soul. A being or entity which, like a god, was in complete control of and responsible for everything that took place within that world.
Two of these world-beings who found no joy in their solitary existence, drew near one another in the void, and sang to each other. While this communication eased their solitude, it only increased their mutual desire for companionship. And so, after a time, they endeavored to merge.
Needless to say, their act destroyed the Balance. Both realities burst open, and in a spreading wave around them all the other realities shattered. The very nature of the universe shifted as a new Balance was found.
The simplest way to describe the universe after the Shattering, is a great flat ocean, spreading out in all directions without end. Yet instead of water, this "ocean" is filled with two primal forces, which are ever at war. Think of these forces as Life and Death, or Creation and Destruction. These two forces are ever striving with one another. Life strives to bring things into order, into balance, by creating. Death naturally destroys what Life creates, and the whole process begins again. As a result of this endless battle, the whole of the flat Sea-verse is a chaotic storm where whole worlds are created and destroyed in the space of a few heartbeats.
Floating on this sea of chaos are the scattered pieces of all the broken realities, which we call Shards. Each Shard is a stable piece of reality that contains within it a piece of the world it once belonged to. These Shards range in size from a few miles across, to hundreds and sometimes thousands of miles. The only thing protecting the stable reality of the Shards from the chaos outside is the Veil: an invisible barrier which separates the Shard from the Deep.
The Sleepers and The Well
In addition to the physical matter of their previous worlds, each Shard bears a remnant of the being which once had protected it. Each of these entities has responded differently to the trauma of the Shattering. For most, its as if they're in a deep sleep, dreaming a billion dreams with all the broken pieces of their soul. These Sleepers manifest in their shards as a well of power which is often undetectable to the inhabitants. In some Shards, those where the Sleepers do not dream as deeply, the Well can manifest itself in a multitude of supernatural occurrences. And in a very few, the larger ones specifically, a Sleeper can awaken itself for a few brief moments every few centuries, often to perform some important act.
In most cases, the one thing that each Sleeper awakens for is creation. They create a version of themselves. Mortal, far less powerful, rarely aware of itself at first. In essence, a child. Born without pattern every several hundred years, these children bear the latent power and memories of the being which formed them. In all cases, the birth of such children heralds significant events.
The Deep
One of the most important things to remember about the Deep is that the movement of creative and destructive forces is malleable. Two things have an effect on the Deep.
Shards, as stable pieces of reality, impose some order on the deep around them. Like a planet's gravity well, these effects are more pronounced closer to a Shard's veil and weaken the further one travels from a Shard. These effects, or Echoes, take many different forms. In most cases, the Echoes sent out by a Shard shape the deep around the veil into a semblance of that Shard's environment. Mountains, oceans, forests, similar atmosphere and weather, and so on. The similarities naturally are less and less pronounced and reality becomes more unstable the further into the deep one travels.
Sentient beings, those with sufficient mental capacity and strength of will, can also have an influence on the Deep. A strong enough mind can direct the ebb and flow of shifting forces, and impose their will on reality. This Shaping can be done anywhere in the Deep, to varying degrees of strength. It becomes easier the farther one travels from a Shard. Yet the danger lies in the fact that, the further a Shaper travels from the safety of a Shard's Echoes, the harder it is for them to hold on to the protective "bubble" of reality that they create around themselves. Walk too deeply, and a Shaper may easily be unmade.
The Golden Circle
The story in the Shattered Realms takes place in a corner of the Sea-verse where 6 Shards have drifted into close proximity. The inhabitants, after years of tension and a few short but bloody wars, have formed an alliance with the help of a mysterious group of Shapers known as the Pathfinders. Yet after several centuries the once stable alliance is beginning to fray at the edges. The Pathfinders, whose strength and power had helped to build the alliance, have become more and more scarce, with little explanation given for their sudden shyness. While the Shard-worlds find their troubles multiplying, both inside and out.