Question about Goblin master

Master Goblin is in a map called "Fiend Priests Forest" which is accessible by pressing up on the stone structure in Goblin Forest 2. However if you didn't start the quest, a blue text will appear on the bottom saying "The fog is so dense that you cannot proceed any further" or something like that.
I'm not too sure though, but I think that's it.

That is where the master goblin NPC is.
The boss itself spawns in Goblin Forest 2.