Who is Eagle from Ride the Wind: The Story of Cynthia Ann Parker and the Last Days of the Comanche and what is their importance?

Eagle (Quinna) took John Parker captive, and then he traded him for goods. He fell in love with Pahayuca's wife and ran the risk of retribution. When he and Wanderer were captured by Placido, he taunted their captors to the point that they killed him. Eagle and Wanderer were as close as brothers, and he knew that one of them would be killed that night.