MTL - My Son Might Be A Villain - Chapter 52 My mom said

What happens when a scientist from a futuristic world reincarnates in a World of Magic and Knights? An awesome MC is what happens! A scientist’s goal is to explore the secrets of the universe, and this is exactly what Leylin sets out to do when he is reincarnated. Dark, cold and calculating, he makes use of all his resources as he sets off on his adventures to meet his goal. Face? Who needs that… Hmmm… that guy seems too powerful for me to take on now… I better keep a low profile for now. You want me to help you? Sure… but what benefit can I get out of it? Nothing? Bye. Hmmm… that guy looks like he might cause me problems in the future. Should I let him off for now and let him grow into someone that can threaten me….. Nahhh. *kill*-

Alternative: Leylin is transported from an advanced technological era into a medieval world— except there’s magic. Equipped with “only” his quick wits and an A.I. chip fused to his soul, he sets out to become the most powerful magus the world has ever known. In a land divided into the Light and Dark Magi, the weak can either be cattle or disposable slaves. Only the strong can determine their lives, and only they have the luxury for virtue. Yet strength is only a tool for Leylin, like any other. His goal, in the end, is his own.

He was the merciless Soldier King on the battlefield who sent shivers down the enemies' spines; he was the soldier scoundrel in his squad who could make anyone both cry and laugh; he was the Big Brother everyone in the urban underworld aspired to be; he was the male god in the hearts of young girls and beautiful women; he returned with a mission...Uniting the underworld, establishing an economic empire, he vowed to become the supreme overlord of this world...To prevent the world from destruction, to protect world peace, to implement love and truth's evil, the lovely and charming antagonist, he is Xiang Yu, and he speaks for himself...

Luo Qiu became the boss of a ‘club’ by chance.

It was a weird club that sold strange items and with a servant girl that had 300 years of working experience. Countless people with dreams, hopes and ambitions came to the club to exchange anything precious they own for what they want. They would offer their lifespan, items, and even their soul. Every successful trade would increase Luo Qiu’s lifespan by a little.

“Tribute successful, your lifespan has increased by 99 years.”

As thus, Luo Qiu began his endless life as the club’s boss.

- Description from Novelupdates

There is no rebirth through time, and there is no system of heaven to cut melons and vegetables;

There is no secret book under the cliff, and there is no great return pill from the dead;

There is no such thing as a full-fledged lust with a strange root and a sacred blood.

If it is said that Shi Jianren is an expert who has attained the Tao and joined the WTO,

Then Bai Haonan was a dazed fellow who smashed his head into blood.

The key is that he still feels that he is living a very happy life!

A story similar to the golden right foot,

A story about a dream,

It depends on what tinted glasses you are wearing.

- Description from novelbuddy