Complex sentence: Life among the Cheyenne proves to be idyllic, though Jack unwittingly makes an enemy of another boy, Younger Bear (Cal Bellini); however, Younger Bear eventually owes his life to Jack, who saves him from a Pawnee warrior.
Split into simpler sentences: Life among the Cheyenne proves to be idyllic, though Jack unwittingly makes an enemy of another boy, Younger Bear (Cal Bellini). However, Younger Bear eventually owes his life to Jack, who saves him from a Pawnee warrior.