i’ve seen people talk about thorfinn’s “i have no idea what a slave feels like” line as an example of foreshadowing for future events but if we look at it juxtaposed to the rest of the chapter it’s definitely dramatic irony for the fact that he is already a slave to his revenge.

his single-minded thirst for revenge is what has tied him to askeladd for over a decade and is a powerful enough force that askeladd can use it to manipulate him into doing almost anything – when askeladd talks about how “every man is a slave to something” earlier in the chapter and then duels thorfinn (and, very importantly, absolutely thrashes him when he goads thorfinn’s anger and sense of vengeance) as a “reward” for the task he used him for earlier… masterful storytelling tbh.

plus, in the manga the scene with the slave girl also segues into the introduction of vinland both as a location and as a narrative symbol; thorfinn doesn’t consciously realize he’s a slave to his revenge yet, but like her, he still yearns to be free, to be “somewhere not here”, and that informs his motivations through the entirety of the story, even after the events of the 50-chapter prologue. it’s probably the most powerful scene in one of the most theme-setting chapters of the whole manga.