Abridged Guide to Evil Wikia

Arcadia is a world. It has similarities to Creation and some consider it a kind of mirror image of Creation. It is proven that exceptional events in Creation will leave an echo in Arcadia. The ritual of the Dead King in Keter being one such event. Therefore a connection between Arcadia and Creation exists.

In a dialogue between Neshamah and the Intercessor, it is hinted that Arcadia was created before Creation and was used as a prototype and blueprint for it, after the Gods realized they could not achieve their goals through Arcadia.

Fae and other powerful beings can travel to Arcadia from Creation and back. The flow of time may be different between the worlds however. Distances in Arcadia may or may not correspond to their "mirror-distances" in Creation.

There seem to exist continents in Arcadia, as the Arcadia of the continent on the other side of the Tyrian Sea is completely different and not inhabited by Fae.

The currently explored part of Arcadia therefore only corresponds to Calernia.