Yin-Yang Harmony System - Chapter 265

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

“Is this man not going to divorce me? Why does he still ask me to warm the bed every night?”

Humanity had finally ended the war with the Demon Race and sealed them away, forever.However, they now have to face the treat of the Shadow World, an equally dangerous threat to their civilisation under the rule of the Emperor!Facing only misfortune from a young age, Nikolaus Reinhardt never expected anything good to happen to him.But his world completely changed when he awakened as an Ascendant, and accidentally summoned a member of the Demon Race in his house.Just because he messed around with a god damn book!

Ethen Cole travels to an era where everyone battles with pets. In a world revived by spiritual energy, danger and madness run rampant. Humanity relies on battle pet masters to establish bases and unite for survival.Before the college entrance examination, Ethen Cole is framed and expelled from school, losing his chance to study at the Battle Pet Academy. Just as he feels despair, the Battle Pet System for battle pets activates.“Ding! The Blue Riolux has evolved into a Emerald eyed Riolux!”From then on, Ethen Cole begins his legendary career as a battle pet master.