Crazy Theory: You wake up from a coma and forget everything that happened and enjoy boring normal life.

Otherwise basically agree knighttemplar either stay in purgatory, go into Valhalla (I think going into Valhalla is a boring ending imo.

Or Odin now sees you as the threat because he's a god who can change his mind on a whim. Either he kills you and that's that or maybe you get the chance to fight him and . . .?

I don't know enough about north mythos to make an educated guess on what happens if Odin dies, but you kill him and become Odin? The game ends up being a never ending loop of a purgatory where everytime you see Odin watching you in-game it's actually a previous you waiting for the yet again inevitable battle and reset of the process.