MTL - Self-cultivation of Male Supporting Role - Chapter 6 pay off

Jiang Chen had unexpectedly found himself thrust into a world of cultivation, stepping into the role of a core disciple within a famed sect. Fated to be the villain, his future loomed with calamity. He had plotted against the protagonist, crippling his dantian and leaving him a disgraced outcast teetering on the edge of expulsion. Were it not for an unexpected twist, Jiang Chen’s part might have ended as a mere footnote in the protagonist’s glorious tale. Fully aware of his precarious position, Jiang Chen’s lips curled into a sly grin. Alone, he mused: ’Is the protagonist powerful? Without a doubt.’ ’But will I tremble in fear? Absolutely not.’ ’Why? Because I have the Immortal Great Villain System!’ ’Wait... there’s more than one protagonist?’ ’Well, isn’t that just perfect?’ With a determined glint in his eyes, Jiang Chen declared to himself, ’As the ultimate Great Villain, I will defy the will of Heaven and seize my place at the summit!’

Ji Ling, who was transmigrated into the notorious body, after settling the foreign debts owed by the original owner, was persecuted by peach blossom debts before, and then had a mother who wanted to exchange her for money.

Suddenly, in order to repay her kindness, Ji Ling married her benefactor’s grandson, an elderly young man, in a flash marriage.

In the days after marriage, she summed it up in one sentence: My daily life with the face-blind old rooster.

Gan! !

- Description from novelbuddy

A cultivation story about how a declining sect is restored by a narcissist, a troublemaker, a meanie, an idiot, and a wimpy kid.

- Description from Novelupdates

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