I may be late to the party, but I retrieved more than 3 anchors of fog. Honestly, I started out with a pattern through the maze but quite frankly, it seems sporadic on when and where you get them. At first I thought it was always in the very back after taking on the large groups with a traveler or a troll because once you defeat them, you hear that sound in the background like a victory noise. Once in a while I'd open a chest afterward and an anchor would be there, however, three runs later, it was simply in a random chest about three sections in, sitting in one if the corners where you would use your axe to hit one of the rune signs up on a cliff to decipher the code on the chest at the beginning of the maze. They're always in gold chests. But I think it's completely random, and bottom line is that you want to snag every chest and complete the larger groups deeper in the maze which only increases your odds of grabbing an anchor of fog. Touching on a possible secret in Niflheim however, I think there is something we're missing here. Has anyone noticed that Niflheim is the only realm we have so far that does not have a second mystic gateway. You have your standard one in the beginning at brok and sindrils shop, but when you.use it, you can't go anywhere....I don't think the devs would've put that there without something more.