Blacksmith vs. the System - Chapter 142

On earth, Felix is just a normal guy, a bit of a loner but otherwise normal. In the multiverse, under the rule of The System, he's a caster. Fascinated by magic and hungry to learn, grow and discover, this series follows Felix on his adventures through the integration and beyond.

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

Rosemary spent 18 years thinking she was a member of the wealthy Harris family, only to discover she was a fake rich girl. When the real heiress returned, Rosemary was cast aside and sent back to her poor hometown. But fate had other plans for her, as she soon discovered that her hometown was actually the most exclusive villa area in the country. In a single night, Rosemary went from a modestly wealthy girl to the true heiress of a top-tier elite family. Her biological parents showered her with love, handing her millions of dollars in pocket money, providing access to any car from their fleet, and letting her buy anything from the world’s top designers. As for school, the best institutions were at her fingertips, and if she didn’t feel like studying, she could play with the family company.But what shocked Rosemary the most was finding out she had an ex-fiancé. She couldn’t understand why he kept clinging to her, holding her hand, and trying to kiss her. “Who are you, sir?” Rosemary asked, annoyed. “Sweetheart, I’m your husband,” the ex-fiancé responded. “I don’t have a husband, only a former fiancé”

____this story sets in Japan that developed a little different history from yours.

This is how a Japanese Princess relieves her stress of the day by using the latest VRMMORPG, and while playing the villain there, the first town turns into whirlpool of chaos, smashed the underground organization in one hand and went for a coup. It’s literally a playtime diary of a girl who is called as “Genocider-san”, “Roaming Last Boss”, “A different person plays the game”, “Raid Boss”, “Ruthless”, “Calamity”, and such by the players.