Heretic Doctor Useless Consort - Chapter 866 - : Daoist Sect Declares War!

When a glorious old civilization was toppled overnight, a strange purple moon rose and thus began the Purple Moon Era.

A young man with no spiritual roots. A person who is thought of as trash by others. He constantly acquires various items thought of as waste by the cultivation world. No matter if it is garbage pills or useless materials, he will take them all!

- Description from Novelupdates

After his death, Bern awakens 10 years into the past as the third prince of Kailis, the enemy country.

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!

- Description from Novelupdates