T'an-zao was an explorer from the Plain of Horses who, in 1347 DR, was shipwrecked in Kozakura with his entourage and started life as a bandit. Many times, Niwa Hirotada sent expeditions to eradicate T'an-zao's bandit group but he always retreated.
T'an-zao was a brilliant tactician, fusing tactics from his homeland with Kozakuran ones. He had a very capable cavalry. From his homeland, T'an-zao learned only death and plunder. He was clever but vindictive. However, T'an-zao recognized his weaknesses.