So, I was hoping I could get some confirmation by the devs actually on the story, but that might be wishful thinking.
I just played through the storyline of Discovery Mode: Viking Age the last two days, and have a huge question about Thorsteinn's and Gunnhilda's fate.
Since the very start Bjorn has been a thorn in the side of Thorsteinn. His false accusations, the attitude on him. Getting in debt, constantly asking Thorsteinn for help. Near the end Thorsteinn talks about his debts and that he owes money to some shady people. After the wedding in Yorvik he once again asks for help, but this turns out to be false, as Mimir confirms he was betrayed by Bjorn. And that Thorsteinn is dead.
I have two questions related to that:
1) Did Bjorn kill Thorsteinn? Or was it the people he owned money to that killed both of them? We don't even know if Bjorn is alive, just that Thorsteinn and Gunnhilda are dead. That leads me to the second question.
2) Was Gunnhilda also murdered? When Thorsteinn leaves with Bjorn and sends Gunnhilda home, we get a dream-like cutscene were Gunnhilda is searching for Bjorn, but is never within her grasp. Then Bjorn is in Jotunheimr and thus dead. But when he ends up in Fokvangr, Gunnhilda is also dead. So either Gunnhilda died not long after Thorsteinn or years and years have passed in Midgard during the "Where Fates Align" memory until she died of old age. I personally feel like it was the first, possibly murdered by Bjorn too, maybe that dream-like sequence was actually her being poisoned by Bjorn.
I can only speculate and there aren't even many sources ingame that explain the ending, just a few hints. It left me with so many questions, I was really hoping someone at Ubisoft could explain this to me, if they are allowed to do so/want to of course.
Somehow I had grown close to Thorsteinn and Gunnhilda over the last two days, even though it's a not so real long story. The ending is unexpected and kinda sad. They were together in the end, but who knows what happily live they could have lived without Bjorn. Meeting Trygg's and Eadith's children in the future etc. Maybe it's just me though.