I Have an Underground City

Xu You accidentally transmigrates to another world and starts with a dungeon of his own. Faced with an unfamiliar world, he is fortunate to activate a mysterious System! But who could have guessed the System would be such a pain? In the end, he still has to rely on himself. Xu You says angrily, "When I have an army of a million and stand at the gates of the world, that'll be the day this lousy System meets its end." "Detected Host disrespect toward the System. Punishment initiated!" "Ah! Great System, I was wrong. Please let me off this once..."