Leveling Up And Becoming Undefeatable - Chapter 12 - F*** Your Ancestors

Su Yu was in a third rate university when the “Sky Holes” appeared, his school fell through the “Sky Hole” and appeared in the middle of a forest that was teeming with terrifying creatures.

Witness a fearsome transformation that originates from his hand…

- Description from Novelupdates

Yoon Eunah was engaged with Lee Young-soo by their parents. But the marriage didn’t go as it was planned.Faced with Eunah’s absence. Eunbi, her younger sister ended up marrying Young-soo against her will to save her parents pride and self-esteem.Neither her’s nor his parents came up with a plan of involving Eunbi and Young-soo into the marriage. It was full and fully planned by Young-soo, he emotionally advice Eunbi by using her family weakness as his strength to get her acceptance to marry him.Eunbi was suspicious of Young-soo’s plans for marrying her whether, did he married her for revenge? (or) did he married her for her wealth? What will happen when Eunbi finds out the real reasons why Young-soo has married her, will she forgive and accept him as her husband and lead a happy life?

The main character is reborn as a character from a game he played in his previous life. This character falls into ruin along with the villainess, spending the last of their years together. A man named Kururi Helan.

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