What is the name of Sioux Chief encourage Native American tribes to resist being put onto reservations and fight against the US government?

The Sioux chief known for encouraging Native American tribes to resist being placed on reservations and to fight against the U.S. government was Sitting Bull. He became a prominent leader and symbol of Native American resistance during the late 19th century, particularly during conflicts such as the Battle of the Little Bighorn in 1876. Sitting Bull advocated for the preservation of Native American culture and sovereignty in the face of U.S. expansion.