The movie is filled with supernaturally tinged encounters between Amleth and various “seer” characters. They prophesy and give instructions that keep him on a path that seems so inevitable that, for an “action movie” full of violence and adventure, the movie is never particularly suspenseful, even when it’s plunging the viewer into the middle of close-quarters battles, scenes of atrocity and torture, and narrow escapes. I suppose some would consider the approach disappointing or tedious or simply not appealing. But I found it hypnotic and invigorating, because by entering into it, you accept the mindset of another culture from another time, and it briefly rewires your brain. This is the kind of world where you have a dream that feels real, and the information contained within it is delivered by a scary figure (or in one case, a severed and tongueless head with artificial eyes) who also feels real, and you awaken into a “real world” that doesn’t feel all that different from the dream. The long-take direction (elaborate camerawork and choreography, few or no cuts) emphasizes the idea that all of these characters are locked into a path and can only go forward. (For more about the making of the film, see my colleague Simon Abrams’ book The Northman: A Call to the Gods.)
I don’t think characters in Eggers’ movies have interior lives, at least not in the way that post-Freudian secular people who grew up in a world of self-awareness and self-inquiry understand it. Insight in Eggers’ films is not something that a character typically seeks and discovers on their own terms, but by having an encounter with some eerie being (a woman in a headdress, a cackling man in a cave, etc) who interprets dreams or reads entrails or something along those lines. And you accept it because it’s the kind of fictional universe in which metaphors are real, prophesies are sometimes misunderstood but never wrong, and gods not only exist but have plans for us that we don’t get to have a say in.
The question of whether you have free will is quite beside the point, because you’re locked into a journey described by others. You’ve been told by your elders that this is how the world works, and yes, indeed, that’s how it works, and you have to roll with it, not fight it, even when you have a better chance of happiness if you go some other way. There’s a moment late in the film that’s “The Northman” equivalent of the scene at the end of “Heat” where a thief is faced with the choice of getting revenge on the snitch who sold him out and risking arrest or death, or letting it go and starting a new life with the girlfriend who adores him, and the fact that it could only go one way is what makes the tale a tragedy. Is “The Northman” a tragedy? No, I don’t think so—because these characters wouldn’t even understand the argument for why they’re in a tragedy, and such discussions would be so irrelevant to their lives that they might slit your throat to shut you up.