Became a salted fish pretend heiress and handed over the system - Chapter 92: Research

A polite and lethargic boy was reincarnated in another world as a vampire bishoujo.

For his sake, she was willing to abandon her career as the best actress and be his wife. With her own network, money and unscrupulous methods, she helped him rise to the top of the world. He, on the other hand, held another woman in his embrace and kicked her away with no mercy. It turned out that all he ever wanted was her rare blood type, her six-month-old child’s cord blood. It was her life… When she opened her eyes again, she returned to her 20-year-old self. Time repeated and her life rewound. In this life, she would live well.

The unparalleled Demon King Ye Xuan, who was able to heal the death or the living alike and holder of the medicine Holy Scripture, was betrayed and killed by his fellow Demon Kings. But he reincarnated into the body of Ye Xuan, the prodigal son of the Ye family and vowed to himself that he would return to his peak and take back everything that belonged to him!

- Description from Novelupdates

Xiao Ran transmigrated to a fantasy world. As a dungeon guard in the Celestial Dungeon, with a special floor called the Purgatory meant for powerful demons and martial arts experts, he faced a huge challenge from the start. The Eldest Princess acquired a forbidden martial arts technique and was banished to the Purgatory. However, no one was powerful enough to restrain her. All the dungeon guards were defeated. Xiao Ran stepped up and declared, “Your Highness, it’s better for you to behave yourself on my territory” and effortlessly subdued the Eldest Princess.

He progressed from imprisoning the Eldest Princess to delivering the Great Xia Kingdom from the evil clutches of various demons and evil martial arts experts.

…

Xiao Ran was the mastermind behind the scenes.