Yeo Woon is a man with a pale handsome face, long black hair and matching black eyes, white skin with tight, well-built muscles. He was notorious for being kind to his subordinates and loved ones but extremely cruel and ruthless to anyone who dared to show hostility especially his enemies.

Yeo Woon was a member of the Cheon Family, the highest-ranked family in the Demonic Cult. Yeo Woon was born to Cheon Yu Jong, the 23rd Lord of the Demonic Cult, and his seventh wife, Lady Hwa.