The Son-In-Law's Servant Went from Useless to a Murderous God

A modern special soldier traveled through time and became a useless son-in-law, who was thrown to the dock to work as a servant. He used modern military theory to train a team of killers. When a rival family sent a killer to attack at night, his team of servants came back to kill the entire family. The head of the family asked tremblingly: "Who are you?" He wiped the knife and smiled: "A person who wants to eat soft rice."