Who is Yellow Kidney from Fools Crow and what is their importance?

Yellow Kidney is an experienced horse-taker who leads the horse-taking raid against the Crows. This raid is life altering for Yellow Kidney as well as for Fast Horse and White Man's Dog. Yellow Kidney is one of the Pikuni men who own a many-shots gun. While on the journey to steal the horses from the Crow he second guesses if the youth who accompany him are ready for the venture. The only other experienced horse-taker is Eagle Ribs whom he uses as a scout. During the journey to the Crow camp, Yellow Kidney gets to know White's Man's Dog better and sees in him an honorable youth.