Transmigration After Becoming Love Saint - Chapter 7 - 6 Xu Gua! Cause and effect!

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

Who, in the ancient mythology, held an artifact and killed the first emperor of the human race?

Who, at the beginning of ancient times, closed the gate of the God Realm, Jedi Tiantong?

Who set a lifespan limit of only one hundred and thirty years for the people, and even the Great Emperor was not spared?

Who, turned into a black hand that covers the sky for eternity, shrouded the world?

…

Yang Shou on Earth: “Yes, yes, I did it all, I just want to live.”

- Description from novelbuddy

The empire has turned into the land of the undead due to a spell gone wrong. God summoned heroes from countless worlds to purify the empire and plant new hope. Lee Shin Woo, an ordinary earthling, was also summoned. As an undead, that is.

Ding![QUEST: Defeat the Abyssal Realm Lord. Grimzark, The Dread of Tyrant.]DESCRIPTION: The Abyss Realm was once under the rule of Goddess Zyraena, but it fell into darkness when the Fallen God, Grimzark defeated it's guardian and took control.OBJECTIVE: Reclaim Goddess Zyraena's realm.Reward: Hidden Class, Gold Coins, Experience, Legendary Weapon, Return to Earth ,REUNITE WITH YOUR MOTHER Etc.Time Limit: None.Penalty for Failure: Death.You will be transported to the Abyss Realm in 5..4...3...Han Seojun is frail and barely more than skin and bones from a life of poverty, was raised by his hardworking mother with no knowledge of his father. At 18, he inherits the Ancient Infinite System, a power passed down for generations from Goddess Zyraena, The Former Echidna (Goddess of Monsters).Over five months, the system transforms his weak body and improves their lives. Just as Seojun is about to take his dream veterinary exam, he's suddenly summoned to the Abyss Realm, a brutal world where only the strong survive.After 500 years of Endless battle with his Guardian Cerberus named Huno and Hydra named Silla, Seojun finally reclaim the Realm.Ding![Congratulations Host! You have max your level! LV. 999,999]Ding![You have obtained a Hidden Class: SSS-Rank Abyssal Tamer.][Title Acquired: Lord of the Abyss]Upon returning, 5 years had passed since his dissapearance and finds the world transformed. Dungeons and monsters are rampant, and people now possess skills and classes granted by a system called global system Where Earth transformed A Game into Reality.People granted is known as the Awakeners and Seojun, protected by his Infinite system, rejected the global system. He is classified as a glitch—a Non-Awakened by the Global System but his level just reset to 1.