Won Hyo

Won Hyo was a high-ranking sorcerer from Jushin, and a former ally and friend of Munsu. Despite his demon heritage, he ultimately rejected his race's bestiality and mindless massacre of humans, choosing to side with Jushin during the war against the Kaidaten. Over time, he came to despise his hideous demon body, preferring to assume human form through his magic. Along with Won Sul, he switched allegiances to Aji Tae following Jushin's fall, helping him grow the narcotic Yang Gwi Bi plants. While in Aji Tae's service, Won Hyo eventually lost the morality he once held dear, becoming as malevolent as the kin he once fought against. This ultimately resulted in his being unable to maintain his human guise, and began taking human sacrifices, devouring their souls so that he could keep a human appearance. He is killed by Munsu and Bang Ja. Just before his death, he tells General Munsu that he hopes that Munsu would remember him as one who had fought side by side with him, instead of the monster that he is now. (Source: Wikipedia)