In 13th century, Mongol led by Genghis Khan, rapidly expanded its territory. Goryeo (Ancient Korea) was no exception from its claws.

One of early clashes between Mongolian army and Goryeo army saw a resounding defeat for Goryeo, and in that defeat, a defeated general, who survived, walked into a forest at night to die and met a kumiho (9 tailed fox)...