Cheonmahaeng

That was the beginning... the lonely wolf's journey to Changrang-Hu death and the legend of Cheonma (天魔) represented by Cheonma Gojeon! The story of a lone warrior who left the greatest mark on the history of martial arts. It was the beginning of a legend that later generations would call Cheonma Haeng (天魔行),

(Source: Mr.Blue, translated)