I've Already Confronted the Five Kage, and the System Just Arrived! - Chapter 258 - 259

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

I transmigrated into a webnovel as the pathetic young master villain.You know the type that bullies the protagonist, gets face-slapped repeatedly, dies embarrassingly to show the hero's growth.That villain. Yeah. I'm that idiot.Except I'm not playing along. I'm not going to! I'm not even going to try![WELCOME TO THE VILLAIN REFORMATION SYSTEM][MISSION: Don't avoid being a villain. BECOME THE BEST VILLAIN.]The hero? A manipulative hypocrite hiding behind righteousness.His harem? Heroines trapped by circumstance and narrative.The villains? Actually had legitimate reasons all along.I'm not here to be a stepping stone, I'm not here to redeem myself into a side character and I'm certainly not here to help the hero win. I'm here to show them what a REAL villain looks like.The Strategic, charismatic and magnificent that I so much likes to read about.The Academy's Worst Villain isn't the one who bullies weaklings. It's the one who steals the protagonist's fate, recruits his harem, and rewrites the story.Let's see how the hero handles a villain who knows every move he'll make.-----------------Additional tags.Drama.Harem, Beautiful Female Lead, Antihero Protagonist, Clever Protagonist, Strategic BattlesFaction Building, Romantic Subplot, Face-Slapping, Revenge...Note: This is not a dark book and it's a very fast pace book.

Sagiri was born in silence, no cry, no breath, no heartbeat, until a pulse of ancient energy tore through the air and marked him as the last child of a dead people. Cold, disciplined, and frighteningly calm for his age, Sagiri has spent his life hiding a power even he doesn’t fully understand. He does not smile. He does not fear. He does not allow anyone close. Because the thing living inside him 'The Echo' never sleeps.