I Became a Ruined Character in a Dark Fantasy - Chapter 51

System: You are the only human who meets the binding requirements of this system, please bind with me!

Using the ability to freely travel between Earth and the fantasy world so he can… become a porter of two worlds…?

Bai Yang’s objective was to establish a production line that would yield hundreds of millions of pills, pellets, and artifacts…

- Description from Novelupdates

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!