In Valhalla Rising, the final chapter (IIRC, Chap IV) is titled "The Sacrifice."
This is one of the few things I've not been able to figure out on my own, for sure. Why was the chapter called that? I don't believe One-Eye/Odin sacrificed himself for The Boy.
Although the Indians turn and leave The Boy at the end, this didn't really do The Boy any favors, alone, in a strange land, where he isn't even able to communicate with the natives, he's simply going to die of starvation.
(As always, edits are welcome and if this is too broad, I won't complain if closed.)