Though I like to try to make things clear in the comic itself, there are a few things the characters just aren't going to explain to each other because most of them already know. So I figure it'd be helpful to have a little introduction to the world of the story.
The Ka'ei are a magical people who live in a "parasite" dimension attached to Earth, which they call the Realm. It is not a complete world and its surface covers a very small amount of space compared to a real planet. It is bounded at its edges by the Border, which is a one-way passage to Earth. Earth (called by the Ka'ei "the other world") is also accessible by teleporting. Teleporting is also possible to and from most places in the Realm, although not all. Time flows differently in the Realm; for every year there, 100 years pass on Earth. The Realm of the Ka'ei, like any parasite, is kept alive via its attachment to Earth. It doesn't even have its own weather, but remains a general early summer - usually.
This way of things was upset once before, starting thirty-five years prior, in what the Ka'ei call "the Conflict". Over a period of five years, one of the Ka'ei murdered and otherwise indirectly caused the deaths of hundreds of his own people. As he drew on the power source he had found, he destroyed the balance of the energy sustaining the Realm. The Conflict only ended when he was finally killed, but it had permanently changed Ka'eian society, previously in a golden age, leaving none of the survivors unaffected. There are currently less than 300 Ka'ei left, and the Realm itself is still regaining its equilibrium from the drain of its power. This is the state of things as the story begins.
Jahei, mentioned occasionally, means something like "source". The Jahei exist in the Void and control the souls and reproduction capabilities of the Ka'ei. Very little is known about them but they are often seen as having "wills" and are the closest things to gods that the Ka'ei possess. They release a soul when a child is conceived and they also predetermine each soul's Match - one or a few others with whom that person will be able to reproduce. Death sends the soul back to its originating Jahei, where it rests before potentially being reborn.