The AFK Farming Software: I Became Invincible Without Knowing It - Chapter 368 - Late-stage Grand Unity Mystic Immortal, Heaven and Earth Great Dao Fragment

In novels with a stud there is always a Senior Martial Brother like this:

In the early stages of the novel, his innate talent is high, his cultivation is good, his appearance is handsome, and he has an intelligent, cute younger Martial Sister as a fiancée.

In the middle stages of the novel, he is caught unprepared and defeated by a young disciple (the protagonist) in the sect who’s hardly remarkable at all. From then on, he falls from his godly altar and loses his brilliance. Even his young Martial Sister leaves him for someone else.

In the late stages of the novel, he continues to turn dark, going down the Demonic Path and becoming the major villainous boss. However, the protagonist still ruthlessly defeats him and his soul is eternally sealed.

Once Qin Mo opened his eyes, he discovered that he had become this Senior Martial Brother.

- Description from Novelupdates

This is a strange and inexplicable world…Mountains, water, stones, flowers, grass, trees, wood, the Sun, moonlight, stars… All creation under the Heavens and Earths are sources of energy. In this world, there are all the classics from his previous world, but there is a new addition: The Law of Dao. Fang Zhengzhi was conflicted. I can obtain power from reading books? Should I read Tao Te Ching first? Or should I read The Art of Becoming Invisible? What about the Analects of Confucius or… The Golden Lotus? With The Law Of Dao as his foundation, can Fang Zhengzhi master the Dao of All Creation and open the gate of God?

A mysterious natural phenomenon caused the Earth to be plunged into darkness. The world turned into an endless bloody chaos and mankind is on the brink of extinction…

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!