Apocalypse King System - Chapter 198: Sister’s Good Morning Kiss

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

Yohan wakes up ten years in the past, back when he still lived with his uncle and hadn’t yet lost his parents’ massage parlour. With a strange book filled with wellness techniques in his hands, he decides to live differently this time—more aware, more purposeful, and maybe even more fulfilled.

One-eyed Wolf Lecan is a skilled adventurer who has conquered many dungeons all over the world. He had been going solo for a long time, but in the last three years, he’s had a partner. That partner jumps into the black hole together with Lecan, and both go their separate ways as they fall into another world. Dungeons and magical beasts also exist in that world. After learning the native language, Lecan goes on a journey. Meeting a good teacher, Lecan studies medicine making and magic under that teacher, and begins his dungeon explorations for real.