Originally posted by BadBaneRat:

i don't quite follow you, so it is in game but something happens if i try to explore? how do i know what it is if i stumble upon it? weird for it to be in game but not explorable, if i read correctly...

Valheim loads the map as you explore it, meaning unexplored areas do not exist. Mistlands can be entered like every biome but NOTHING is in it, as it is not made yet.