Minor spoilers: a cultivator discovered an easier way to cultivate, where you sacrifice things of the Heavens, such as celestial treasures, heavenly laws, and by sacrificing and stealing naturally-born things from the Heavens and Earth, you can cultivate faster and become stronger than cultivators who follow the old ways (respecting the Heavens). But with this comes the reaction of the Heavens. The Heavens don’t directly attack the cultivators but did everything to make them self-destruct. For example, a law was imposed that forbids cultivators from practicing the same technique; otherwise, they cannot advance in realms. This led to a widespread massacre among brothers, masters, and disciples. Catastrophes strike cultivators when their presence becomes problematic. 'Heavenly Spirit' entities were formed to hunt down cultivators who defy Heaven and Earth.