Son-In-Law from Another World: I Rely on the Knowledge of the Earth to Defeat Magic

A graduate student of National Defense Science and Technology + an agent traveled through time to become the most useless son-in-law in another world, awakened the knowledge extraction system of all realms, relied on the knowledge of the earth to crush magic geniuses, and went from being a door-to-door son-in-law to an independent lord, and then to the king of the continent! Theme: Western fantasy + alien continent + time travel + son-in-law + system + lord construction