I'm betting we'll get frost giants in the far north

My other guess is that the boss of the GAME will be in the ashlands, and it will be the player, serving their role as a champion of Odin, facing off against the Surtr the jotunn

In norse mythology, Surtr will "come from the south with flames, carrying a bright sword" during Ragnarok. It seems reasonable that the devs wouldn't have our nameless viking hero stop all of ragnarok or anything else so over the top....but a trial by fire in Valheim to determine Odin's champion to stand against ONE of the foes of Ragnarok....that feels like it would be a suitably heroic climax to the game while still being vaguely plausible.