Qin Lie accidentally transmigrates into the world of Journey to the West, taking on the identity of the Bull Demon King. Right from the start, he slays a fallen demon god general. Unwilling to become a pawn of the gods and Buddhas, he relies on a system and extraordinary strength to unite the demon race, seize opportunities before others, and take on the heavenly soldiers and Buddhas head-on, fighting alongside Sun Wukong. Along the way, he settles scores with traitors, exposes the Heavenly Demons' conspiracy, storms Mount Ling, and battles the Four Imperial Sovereigns, greatly increasing his cultivation through countless trials. When the great calamity arrives, he refines Pangu's primordial essence to face the Demon Ancestor. Joining forces with powerful figures from the Three Realms, he brings the catastrophe to an end, establishes the Demon Court, and ascends to become the greatest Demon Emperor of all time.