Ultimate Villain's Return as a Doctor in the Cultivation World - Chapter 90- Snake’s Anger

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

At 18, Alex Kain is whisked away to Eryndor, a game-like realm where he gains 'Skill Synthesis', a talent to fuse skills into godlike powers. Battling monsters and conquering dungeons, he builds a harem of strong women drawn to his might and charm. With the power to return to Earth bearing incredible resources, Alex faces a growing threat that endangers both worlds in this epic of adventure, romance, and ambition.

There was a woman. Born as an illegitimate child and raised under the strict control of the queen, her world was as small as a well.

There was a man. He was forced to marry a woman who was his brother’s political marriage partner. His world, which was infinitely wide, became smaller.

The woman’s original sin, and the man’s resentment. “I should have just died instead…”

“You need my help, Tesoro. You choose. A marriage with me or be torn apart by them” His voice was cool as though this wasn't a matter of life or death.I didn't want this life. My father had gambled a lot and left me with a lot of enemies and now I needed the help of Don Vincenzo LaRosa who was my high school bully and now the Don of the most powerful mafia family in Italy if I was going to survive it.It was just a marriage of convenience but I realized something. He wasn't helping me out of a good heart. I had been sold without my permission to him. I was the mafia's pawn.