Luminae: Who's Afraid of the Dark?

Yet another map. I used MS Paint to slap some legible labels on this one.

The rough idea of this world is that the "heavenly" force of light/land reached down and touched a formerly dark world of water. The light/land and dark/water sides are now battling over who will control the last realm of sky. Spirit is a neutral realm from which each side draws their power.
I think that there will be a fairly balanced ratio of earth and water in this world, but Light is hopelessly overwhelmed by Dark - like a candle in a vast cave. Maybe this mapped area is the last remaining hold out of Light and solid ground because the Dark has destroyed all other pockets. The rest of the land mass(es) have been overrun by evil and darkness and the land is no longer "stable". The terrain has been scarred and warped by the dark powers and battles. Solid ground was never meant to coincide with the shifting flow of dark magic and the unnatural combination has spawned unholy monsters.

I like to think that the territory between the Crescent and Ring rivers is fairly stable, but in a state of constant warfare. Maybe Light magic isn't as reliable in this area while Dark hardly falters at all. The peninsula beyond the Ring River is the kingdom of Luminae, and while outnumbered by the surrounding darkness, its inhabitants are still brave and valiant in the face of peril. Their faith and power remain strong against all odds and the concentration of hope, will, and Light just might be enough to turn the tide of war.

That's where I leave off and let others' imagination take over. What does the world look like? Who are the people/creatures that inhabit it? How does the magic work? Can the Light win? Should it? What will happen if it does or does not?