MTL - American Comic: Create An Oasis at the Beginning, and the Rise of Mutants - Chapter 79

Su Mo, a late bloomer, was introverted and bad at socializing with strangers.He thought his life would stay pretty ordinary, but everything changed when he started playing the popular game Star Ring. He unexpectedly rediscovered the joys of life and set off on a journey to claim the throne.

In a world of swords and magic, where Dragon Knights and Grand Archmages wield powers capable of destroying the heavens and shaking the seas, the legends of their prowess echo throughout the ages.In this world, Sylvus, having crossed over from another realm, opens the Eastern Elixir Shop with a unique system that grants him mastery over ancient elixirs.Within this humble shop, elixirs from the eternal archives of Xianxia are available—each more powerful and mysterious than the last.A Nine-Star Saint Archmage toils away in the shop, working to repay his debt.A Nine-Star Platinum Knight pleads with the shopkeeper, desperately hoping to buy just one elixir.Even God Mages and Divine Knights engage in fierce battles just to secure the coveted Nine-Transformation Golden Elixir before others.

There is nothing in the world that cannot be solved by a transaction, if there is, then make a pure (ang) clean (zang) transaction.

If you say it, you may not believe it. The people who have traded with me are all over the world.

Trading is a great cause that is beneficial to physical and mental health and that people cannot refuse!

- Description from novelbuddy

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!