Summary
Gu Yangchun, once a member of the Orthodox sects, fell from grace and became a demonic human under the rule of the Heavenly Demon.
His life as a demonic human was plagued by regret, as he carried out numerous evil deeds—not by choice, but under the commands of the Heavenly Demon.
During the Great Orthodox-Demon War, Wi Seol-ah, who vanquished the Heavenly Demon, a force so powerful it brought the three supremes of the Orthodox forces to their knees, captured Gu Yangchun. Imprisoned by the Orthodox forces, he endured the consequences of his sins.
Despite the remnants of his morality, Gu Yangchun died after revealing crucial information about the Demon Cult to Wi Seol-ah, driven by a binding spell the Heavenly Demon had cast on him.
For reasons unknown, Gu Yangchun found himself regressed to the time when he first met Wi Seol-ah. Realizing this was not a mere dream, he resolved to live a peaceful life. However, shadows from his past life began to close in on him, one by one.