The Cosmology of Earssea

Earssea is a large world, but it's bigger than it appears. Two pocket realms exist and coincide with the real world, Shadowfell and Fantasia (or Feywild). These realms are reflections of the entropic and chaotic natures respectfully, so they are in fact a part of Earssea and effect the real world in subtle ways.
In Einsteinian space, Earssea is a ringed globe, 2nd planet from its sun, and has a moon orbiting it that is a bit smaller, but not by much.
Here's where it gets weird.
There's something in the rings of the planet that enforce reality in Earssea. A rock can fall from the heavens, but rifts in reality are both rare and difficult to produce. While this doesn't seem to apply to planar gates to and from the aforementioned planes of Shadowfell and Fantasia, it does apply to anything outside that sphere of influence, Heavens, Hells, the Astral plane, Limbo, etc. They are blocked. Strangely, this doesn't apply to pocket dimensions, although, if one is breached and the enchantment is compromised, any lost items tend to be found in either the Shadowfell or Fantasia.
As a result, gods, deities, demons, devils, and eldritch horrors are few and far between on Earssea. They are able to influence, but they always seem distant.
A certain magister has been trying to circumvent this block, with some success, although it has been ill-advised. For all this has happened before, and will happen again...