Undercover as a Deliveryman

"Ryan Grant, heir to a legendary martial master, became the live-in son-in-law of the Lewis family as a nobody, taking a job as a delivery driver to experience the full range of ordinary life. When his training was finally complete and his martial arts reached perfection, he stood against the Overlords to defend the nation's security, earning glory that would never be forgotten. But the Lewis family valued wealth over character and ultimately turned their backs on him. The Sheen family, meanwhile, threw their weight around and bullied Ryan without restraint. Ryan answered with an iron hand, punishing evil, helping the innocent, and upholding what was right."