Hojo Tokimune, Japanese Shogun - Refused the money requested by the Mongols and the Mongols sent multiple invasions into Japan and all of them ending in an upset for the Mongols
They practiced religious tolerance, treated their soldiers well, promoted based on merit, rather than birth, and established a postal service as well as their contribution to law.
Up to 40 million people were killed across Eurasia during his descendants' conquest. That was 10 percent of the world's population killed, not including the plague.