I am sure someone on here has already mentioned this idea. Probably tons. However, doesn't mean I'm not gonna bring it up!
I am currently in the mountains, and I keep seeing those big stone slabs with Ulf the Brave mentioned, and it says how terrified he is of Moder, and that he's been here for 3 summers (iirc)
What if the reason we have been sent to Vlaheim is because Ulf eventually went insane? Ulf couldn't complete his task, so we we're next in line. Ulf has been here for 3 summers (minimum), and he is so terrified of the creatures that he created these stone slabs, not knowing if anyone would ever actually read them. What if, sometime later after updates have been put out, after we get some new biomes, etc., what if Ulf becomes some sort of boss? He goes from Ulf the Brave to Ulf the Undying, or Ulf the Mad, or…you get my point.
Maybe he is a boss of his own biome, or maybe he's a hidden boss somewhere on the seed. I'd say Mountain biome or later. Wouldn't want to find Ulf in the Meadows, ya know? Anyway, only one Ulf per seed (as there is only one Ulf), and it may or may not be required to complete the game, but if he is killed, he drops something special. Tons of gold and jewels, maybe a weapon, armor, etc. If he dropped actual items, it would give people another reason to keep playing, as the single Ulf for the seed they're on dropped a helmet, but you still needs pants, cloak, and a mace. Boom, new seed, go find Ulf, kill him, hope he drops the thing you want
Maybe the devs are already thinking about this, but I'm one of those theorist types, and I like the idea of this man named Ulf, that we know nothing about except that he was here before us. Did he die? Is he still around? What happened to him?