What role did Native Americans play in the US Civil War? Objective The Forgotten Warriors of the Civil War is the story of the tragic effect that the American Civil War had upon the tribes of the Indian Territory (modern-day Oklahoma). More than any other particular group in the United States at the time, the Cherokee, Chickasaw, Choctaw, Creek, and Seminole (the Five Civilized Tribes) were divided between loyalty to the Union and the secessionist Southern states. This lesson will teach students about why this “civil war within a civil war” occurred. Background When the Civil War began in Apri Duration: 60 Minutes.