Hassan-Is-Sabbah’s Assassins
Hassan-is-Sabbah was also known as the Old Man of the Mountain. He taught his followers that there was nothing honourable about a leader who lived in luxury while his people were poor.
His followers were trained in combat and were given the mission of killing any leaders who were corrupt. They got so big, that at one point they occupied over 70 locations and would use their own coded language to communicate.