Final answer:
William Henry Harrison was the governor of Indiana Territory and the archenemy of Tecumseh. Harrison led American forces in the Battle of Tippecanoe which saw the defeat of Tenskwatawa's forces and the weakening of the native alliance. Tecumseh continued his resistance and allied with the British in the War of 1812 until his death.
Step-by-step explanation:
The governor of Indiana Territory who was the archenemy of Tecumseh was William Henry Harrison. In 1811, Harrison led a force against Prophetstown, the Shawnee settlement that was central to Tecumseh and his brother Tenskwatawa's efforts to resist American expansion and cultural influence. This confrontation escalated into the Battle of Tippecanoe, where Tenskwatawa's forces were defeated while Tecumseh was away, trying to forge a Native American alliance in the South. The battle resulted in the destruction of Prophetstown and significantly weakened the native alliance which both Tenskwatawa and Tecumseh had cultivated to oppose American forces. Although Tenskwatawa's influence waned after the defeat, Tecumseh's reputation grew, and he continued his resistance by becoming an ally of the British in the War of 1812, where he ultimately met his death at the Battle of the Thames.