The Etherial Realm is extremely peaceful, with no food or water consumption, no bandits, has Etherium Goop, which acts as a very OP fuel source. Accessed via Ether Door and Ether Key in Mountain biomes. Limited time to be in it however, as after 8 moves, Aethel might kick you out.Â
The Etherial Realm, where the dead go, also suffered societal collapse. So Aethel, the Goddess of Life and Death decided to open the gates and let anyone go back and forth with an Ether Key. But only for short stays.