Martial King's Retired Life - Book 13: Chapter 149

Jeong Yoo-shin, 23 years old, was suddenly transported to another world.In this world, not only was it impossible to return home, but even survival was uncertain.Black-haired humans were called Barbarian and treated as northern savages.There was only one place where he could gain the strength to survive and find a way to return home: the Great Labyrinth.“I must become stronger to survive. And I will definitely go back.”This is the story of a black-haired human’s fierce struggle for survival in the labyrinth.

I lived for you in the last lifetime, everything I did was for you, yet you wanted me to die; so, this time, life is mine to live! This world lied to me, betrayed me, and humiliated me, and I am back to change everything!

- Description from Novelupdates

Kang Min-hyuk, the loser of the checkpoint, gained a high-level magical civilization and everything changed.

Kanda Kyoichi transmigrated to Konoha and became a temporary instructor at the Ninja Academy. Fortunately, he awakened the Mentor System.By teaching others, he could earn rewards.Thus began Kyoichi’s career as a “teacher” in the ninja world.Shisui: “Sensei’s unique interpretation of the Will of Fire has given the Uchiha Clan a true sense of direction!”Asuma: “The essence of the jade lies in protecting the people, with the advanced leading the way for the less experienced. Only then can Konoha become stronger!”Kakashi: “He’s my life mentor. He transformed Konoha!”...Years later, in the memoirs of Kyoichi, now the Hokage, he wrote:“I honestly just wanted to be a life mentor!”