Global Reincarnation: Only I Know the Plot - Chapter 7:

Yang Yang starved to death once, so after rebirth, he had only one wish: food and clothing.

However, in the blink of an eye, Yang Yang heard his uncle say that he had to cut open his stomach to take out the eggs.

Yang Yang: … I advise you to be kind.

In order to protect himself, Yang Yang found out the identity of the father from the birth center, and he embarked on a road of no return.

Yang Yang: Duke, your family is in my hand.

A young unmarried duke: ? ? ?

- Description from Novelupdates

A boy from 21st century Earth, met an accident and later was reborn in Naruto’s Ninja World.
He is born in Uchiha Family and becomes the useless brother of Itachi Uchiha and Sasuke Uchiha…. Let’s see how he changed the Naruto world.

- Description from Novelupdates

“The harder I try to hate you, the deeper I fall for you.”

His presence irked her to the core, but whenever he got out of her sight, she missed him?!

….

A tyrant, known to be the city’s infamous playboy.

As an executive assistant, she was forced to work under him by the most cruel twist of fate.

If losing her job overnight was a nightmare, then working under a boss like Desmond Fort was hell. He was an arrogant narcissist with an ego bigger than the whole of Imperium city, but that was not what angered her the most.

The most infuriating fact was that despite his constant assholery, her heart seemed to stupidly skip a beat every time he gazed at her with those devilishly charming eyes.

She knew she was making a mistake but that didn't stop her from sinking deeper and deeper into his charm.

All she wanted now was to leave! But leaving hell was not nearly as easy as getting in.

There was a mysterious old man who approached the failed swordsman with the “100 million years button”. A magic button which can achieve the same effect as training for 100 million years if you push it.

The failed swordsman who pushed the button had his doubts, but immediately felt tremendous power rising in his body. So he pushed the button many times.

However it was a cursed button. The moment it was pushed, he was confined to the 100 million years prison of time. The first 100 years were devoted solely to training. After 1000 years he had forgotten why he swung his sword. He stopped thinking completely after 10,000 years had passed. After 100 million years he became crippled and finally managed to return to the real world. At the same time losing all his memories from the past 100 million years, the only thing that remained were his sword techniques. “I can become stronger just by pressing the button!” or so he thought and pushed the button many times after that. Foolishly trapping himself in that 100 million years of hell each time.

As he continued this loop, he began to think “If I destroy this world, will I get out of here?” A few billion years later, he finally escaped from the loop.

This is the story of a failed swordsman trying to make a name for himself in the world.