In the 11th century, Emperor Heian became aware of a spiritual opposition threatening the continuation of his family line. To safeguard himself, he summoned masters of onmyōdō, the mystical art of yin and yang. However, tensions and rivalries fractured the unity among these practitioners. Consumed by envy, the sorcerer Dōso harbored resentment toward the exceptionally talented Abe no Seimei. Driven by malice, Dōso cast a curse on the young heir to the throne, transforming the child into a terrifying creature. Seimei invoked supernatural forces and successfully restored the child to normalcy. Undeterred, Dōso resorted to darker sorcery, conjuring a demon with the sinister aim of annihilating both mother and child.