An angel cast from Heaven descends into the Abyss and carves out a kingdom — Hell, or Naraku — becoming its king. He labors to make it beautiful, but the realm can never match Heaven, and it is constantly destabilized by fallen angels who survived the fall, attacking demons and spreading ruin. Weakening with age, the king uses his final strength to produce two heirs: Alex, a golden-haired prince born from his red right eye, and Platina, a silver-haired prince born from his blue left eye. The two have never met, but the king decrees they must fight — the victor becomes his successor, the loser dies. This prequel side story reveals what was happening behind the scenes before the succession battle began.