Because Li Yifan was the best match for the old man's System in terms of worldview, body, and soul, he was chosen to go develop infrastructure and improve people's livelihoods in the Great Tang. The old man spent three days in Li Yifan's dream talking up a storm, only to be cursed at and rejected three times. Enraged, he kicked Li Yifan straight into the Great Tang and forcibly bound him to a System for achieving fame and success. Since Li Yifan still had parents and family in the modern world, the System was designed to be relatively considerate: once the Host completes missions and earns enough points, he can transmigrate back to the modern world once.
