Final answer:
Joseph Brant was the Mohican Native American leader who led brutal raids across the frontier at the behest of the British command during the American Revolution.
Step-by-step explanation:
The Mohican Native American leader who led brutal raids across the frontier at the behest of British command was Joseph Brant, or Thayendanegea. Joseph Brant formed alliances with the British during the Revolutionary War and was instrumental in leading campaigns against American frontier settlements.
Although the Mohawk and their allies, including Joseph Brant, were on the losing side of the war, they fought valiantly and left a lasting impact on the region's history.