MTL - All Things Wrong (Retrograde Gaming) - Chapter 7 This is called upgrade

In his old world, Elric had nothing—no powerful family, no elite degree, just relentless hard work and a passion for healing. Dismissed as a third-rate doctor, he shocked the nation by saving a congressman’s life and becoming an overnight celebrity. But just when his career was rising, tragedy struck.Now, Elric opens his eyes in a world unlike any he’s ever known—a land of swords, sorcery, and strange beliefs. Reborn in the countryside of a magical kingdom, where even a common cold is blamed on spirits, he’s the only one who understands how the human body truly works.With no palace, no power, and no one to trust, Elric sets up a humble clinic in a rural village. Armed with science and sarcasm, he treats the sick, challenges ancient traditions, and slowly earns the awe and fear of a world ruled by magic.Mocked as a fraud. Hunted by rival healers. Feared by nobles and mages alike.But this world is about to learn—Even a third-rate doctor can change history.

Han Yoona, reincarnated into the novel 'The Golden Heir' as the heroine of the novel and she lived her new life without complaints… until she’s killed.Her story should have ended there, but Yoona’s soul wakes up in the body of Luzia de Cazadores, the daughter of the kingdom’s most feared villain, Duke Ramiro de Cazadores.Yoona expects a cold, calculating tyrant. What she gets instead is something entirely different.“The author left out crucial details. Too many.” Yoona thinks, trying to figure out how he became the feared villain of the kingdom.As she gets to know Ramiro, she begins to realize that everything she thought she knew about Ramiro might not have been the full story.“Alright then, forget the plot or trying to rewrite everything. I’ll just grant the original Luzia's wish…”But with rival nobles plotting against them and the kingdom still fearing Ramiro’s so-called villainy, To protect her new family and escape the traps of a story she thought she knew, Yoona must outwit it to prevent the original story's outcome.

This is a story of a little man who walks forward silently, in awe, and strives to chase his dream.

- Description from novelbuddy

A failed investor from 2017 got drunk and woke up in the 1980s. China is just opening up, and the economy is blooming. There is also the dissolution of the Soviet Union, the bursting of the Dot-com bubble and other financial crisis. He used his knowledge of the future and slowly build up his empire.