Mutation Abyss - Chapter 22: Lunatic NAMS

Synopsis: Yang Chen, the inheritor of the divine throne of Hades, was separated from his family at a young age and sold to a foreign assassin organization. Enduring the darkest of worlds, he eventually returned to his homeland incognito. Intending to live a low-profile life as a street vendor selling lamb skewers, fate took an unexpected turn when he married a well-known local corporate CEO. Hoping for a quiet existence, he found himself drawn into the role of a guardian knight due to the presence of beautiful women from various walks of life. As he navigates through these connections, his past experiences and former comrades resurface. Inadvertently, he delves into the world of cultivation in China and uncovers the essence of this world.

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

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates