The Five Worlds

When you walk from Elengkor to Fagóss on the 23rd of Darmonn, you'll end up in Heldágár, and if you don't return by nightfall, you'll be stuck in Ordin until summer.

— Traveller's Observations

The universe consists of five worlds, or rather five dimensions: Ordin, Elverin, Yáðin, Sipmór and Wirmór.
Trollskóg is regarded as the sixth world, but it is not inhabited even how many have tried.

The Worlds