Thank you for Waiting, Mister Tang! - Chapter 22

After annihilating Han, Zhao and Wei empires in succession, the dynasty of Qin is ushering in an unprecedented flourishing age with powerful cultivators emerging endlessly. People take pride in being part of the Qin dynasty. However, Ding Ning, a young lad of humble origin in Changling, Qin, is determined to subvert this dynasty and kill the emperor who breaks in the Eighth Realm.

A Hentai World is a Dangerous Place, Especially if Your Best Friend is a Hentai Protagonist and You Are a Trap.

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