The Elite Assassin Becomes a Flat and Ugly Nerd! - Chapter 148 - 148 Meeting Again

Brutality is my style of conduct! If you can't accept that, I'm ready to fight—that's who I am!Don't mess with me, otherwise, I won't mind teaching you the meaning of “The Return of the King”!!!

Just like how everyone adored heroes in their childhood, a certain young man adored those powers hidden in shadows. After hiding his strength and living the mediocre life of a mob character by day while undergoing frenzied training by night, he finally reincarnates into a different world and gains ultimate power. The young man who is only playing at being a power in the shadows, his misunderstanding subordinates, and a giant organization in the shadows that gets trampled…. This is the story of a young boy who had adored powers in shadows possibly eventually reigning over the world of shadows in another world.

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

It has been adapted into comic：CEO’s Sudden Proposal / Flash Marriage Deep Love

She didn't understand why he took her to get married at first sight. She was just friendly to his daughter at the hospital, but she did not expect that his daughter haunted her to be her mother. It's only the first day of their meeting!

She thought he married her only because of his daughter, but in fact, he was deeply attracted by her kindness and simplicity, and he loved her deeply.

For the rest of her life, Will she love him like he love her?