Each of the ‘Shardworlds’ I’ve written in (Mistborn, Elantris, Warbreaker, Way of Kings) exists with the same cosmology. All things exist on three realms–the spiritual, the cognitive, and the physical. I don’t to bore you with my made up philosophy, but I do have a cohesive metaphysical reasoning for how my worlds and magic works. And there is a single plane of existence–called Shadesmar, the Cognative Realm–which connects them all.
You will never need to know any of this to read and enjoy my books, but there is an overarching story behind all of them, going on in the background. Adonalsium, Hoid, the origin of Ati, Leras, the Dor, and the Voice (from Warbreaker) are all tied up in this.
Is the cognitive realm flat or spherical?
The cognitive realm is this weird thing, where it’s flat, but it’s distorted. You can walk from one planet to the next. So it’s really weird…the spatial reasoning doesn’t work the same way.