The Native American leader killed at the Battle of the Thames was Tecumseh.
Tecumseh was a Shawnee leader who worked to unite Indigenous nations against expanding American settlement in the Old Northwest. During the War of 1812, he allied with the British because he believed their support could help protect Indigenous homelands and preserve a regional confederacy.
The Battle of the Thames took place on October 5, 1813, near present-day Thamesville in Ontario. After the British retreat from Detroit and Amherstburg, Tecumseh and his remaining followers made a stand alongside British forces commanded by Major General Henry Procter. American troops under William Henry Harrison defeated them, and Tecumseh was killed during the fighting.
The exact person who killed Tecumseh has never been established with certainty. Colonel Richard Mentor Johnson later claimed the achievement and built a political reputation around it, but other candidates have also been proposed. What is clear is that Tecumseh's death caused the Indigenous alliance he had built to collapse, weakening resistance in the region.