Ancient Fiend Dragon Emperor - Chapter 1854 - 1853: Avatar Technique

Huang Dan’s pain nerve is innately different from the ordinary people. A little tore in his skin can cause him to sweat all over his body painfully to the point of him unable to make a word out.

Somehow, he began to cross world, following Mr. System to do the tasks…

In the first world, Huang Dan realizes what it means to die painfully and to live to die again.

TL’s summary:
MC suddenly transmigrated and is bind to a system, requiring him to solve mysteries. Born with a higher degree of pain sensitivity, he met different people in the different worlds and learns what kind of emotion smiling is.

- Description from Novelupdates

I, Zhang San, am absolutely a good person!I swear by the eight generations of my ancestors!What!? My ancestral grave just exploded!?

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!”

The main character is reborn as a character from a game he played in his previous life. This character falls into ruin along with the villainess, spending the last of their years together. A man named Kururi Helan.