Goodnight, Mr. CEO! - Chapter 5

Nicholas Crowley is used to scraping by in a world where magic is dying. The modern age has left the arcane behind, and the few remaining practitioners fight over scraps like starving dogs. That, however, is no longer his problem. While performing a ritual, something interferes, and his soul is ripped from his body. He awakens during the Class ceremony as Nick, a kid living on the frontier of the Green Ocean, a seemingly infinite expanse of trees brimming with rare ingredients and powerful creatures. Mana is abundant here, and the omnipresent System allows for feats he had once thought impossible. And yet, not everything is as rosy as it seems. Legends walk the land, and Gods require their due. Will his experience as an Occultist be enough to navigate this wild new world?

The Laughing Demon, Zǔ Zhòu, who had plunged the Nine Heavens into despair, met his demise by defying the Laws of the Dao. However, fate intervened. Transmigrated into a new body millions of years later, with his forbidden bloodline still bound to his soul, he seeks to live this new life as he did before, stopping at nothing, even if it means destroying the Heavenly Dao itself!

This is a story about the protagonist getting the system, going crazy in the biochemical apocalypse, producing aircraft and tanks, destroying zombies, saving good people and killing bad people.

- Description from novelbuddy

When a person dies, they either die light as a feather (aka unimportant) or heavy as Mt. Tai (aka very important).