I saw this movie maybe 7-10 years ago. Sometime in the first half of the movie theres a boy, maybe 7-10 years old, alone in a canyon. At some point he and a wandering man with a sword encounter each other. I think they talk and then the man turns his back to the boy, as if leaving him. The boy gets up and runs to him, clearly going to follow this man wherever he goes. Over the movie the boy gets attached to the man and even though he seems to still acts estranged to him, the man protects him as if he’s the father and accepts a fatherly role to him. Near the end of the movie the man duels this death-like figure and seemingly loses. The boy kneels over the man and searches his body as the figure gets closer in front of him. The boy grabs a canteen and squirts water onto the figure, which seems to disintegrate. I dont remember if the man’s body disappears or gets buried, but at the end of it the boy picks up the man’s sword and wanders into the desert, sort of implying that he will be the man in a few years that finds another boy and the story will repeat.
For some reason I think the movie was in spanish if that helps.