This group of Native Americans would bury their dead in large burial mounds. After a tribesman died within six months a bone-picker would come and remove the bones from the body one at a time. Name the tribe and its most famous leader.

I believe you are referring to the Choctaws, and their leader Tuscaloosa?

Yes, Tuscaloosa was the leader of the Choctaws and was known as the "Black Warrior". The city of Tuscaloosa and the Black Warrior River in Alabama are named for him.