Shinigami Boy Kim

(from ebookjapan):
In the frontier days of the Wild West, there was a boy who was feared as the "Boy God of Death". It was widely rumored that the town he visited would be wiped out.

A man with a baby and a white woman walk across the open fields where a hot wind blows, and the two are pursued by the woman's father, who is furious at their love for each other. Exhausted and on the verge of giving up, the three meet Kim.