The Heavenly Dao sent down rain and dew called Spirit-Evil, and countless seeds absorbed their nutrients. Among them, some grew into the largest trees, sheltering whole areas beneath their canopy. Their root systems also expanded, drawing in even more rainwater, making them increasingly massive. They stored the most nutrients, but they also ensured that no new trees could grow in the shade they cast.
The Heavenly Dao deemed this unfavorable, and so it would dispatch the "Seven Kill Calamity" to destroy these giant trees, allowing them to be broken down and burned, turning into nutrients to nourish the earth once more.
This was the truth behind the Seven Kill Calamity.
Chapter 685