The Immortal King's Demon Diner

A mighty immortal loses his memory after failing to ascend, believing he is just a mountain boy. To trigger his awakening, his grandfather sends him down to fulfill an arranged marriage. Tasked with running a suburban eatery to earn his bride price, he thinks life is simple—unaware the diner is a secret fortress sealing away the world's supreme demons. When evil forces target his shop from opening day, how long can he stay blissfully ignorant before his buried power erupts?