Long ago, thousands of years ago, a Demon fell in love with a human. Because to the beauty of the woman's heart, the Demon broke the bonds with Madvatra and chose to marry the woman without revealing his true identity. That gift, makes their descendants have all forms of power.
Madvatra is a dimension where the Devil King of Deadless resides and is furious. They don't want Mad Demon's blood to be mixed with human form which they think is like a commoner. The gift for the demon who married that woman was a curse to their offspring. There is no safe and prosperous life, for those who have demon blood mixed with humans. Be it Half Demon or Demon Descendant. Everyone will not live happily.
The curse, still persists for centuries. The situation of the Ghostlines (Demon Descendants nicknamed Ghosts) is always in trouble, and is on the verge of extinction when Dark Eaters begin to appear from various places, forming a unit to exterminate the Ghostlines—Descendants of the Traitor.
Because of the threat in the midst of a life that is destined to be full of curses, the Ghostlines are desperately looking for a way to live safely. Starting from disguising himself as a demon and joining Dark Eater. When the blood of the last Ghostline of the Blouise Clan can survive a bloody tragedy, Ren chooses to blend in with human life that is clean from the shadow of the curse.
The Ghostline clan has a large population but isolates themselves and suspects each other until a split occurs. Curses, prophecies and destiny they accept. With destiny on the verge of extinction and threats, the Ghostlines secretly plot a rebellion and compete against each other to conquer the Dark Eater who has power far above them.