Immortals Forbidden in the Mortal Realm

"Heaven does not nurture man; man nurtures himself!" "When heaven sends snow and wind, mortals weave cloth for clothing; when heaven brings drought, mortals dig canals to channel water. Mortals stand in this muddy world, relying on slash-and-burn farming and endless vitality!" "We mortals earn our lives with our own hands, owe no debt to heaven's grace, and need not repay heaven!" — Description from novelcodex.org