MTL - Marvel’s Death Merchant - Chapter 268 Final conjecture

In a world where strength reigns supreme and only the strong are revered, conflict and injuries are commonplace.

This is a world where humans, demons and mysterious beasts coexist.

Humans cultivate mysterious qi. Demons cultivate corporeal bodies. Mysterious beasts cultivate soul perception.

A legend says that in the middle of an endless rainforest, there are extremely powerful existences; they are called demon kings.

Some demon kings have a tyrannical corporeal body, some are experts in illusions.
Some demon kings are proficient in magic, some can even move mountains.
Some demon kings are able to sense things thousands of miles away.

These demon kings rarely appear in the human world. Even if they emerge in the human world, they would reincarnate in human form; assimilating with mankind while seeking to breakthrough realms…

- Description from Novelupdates

Mu Yue traveled to the world of Naruto and became an ordinary chuunin teacher at Konoha Ninja School and a member of the Root Organization.

Fortunately, after awakening the teacher system, you can become stronger by teaching.

In order not to become Danzo’s consumables, Mu Yue worked hard to teach and increase her strength.

“Complete the teaching rated A for the first time and receive the reward – mastery of fire attribute chakra properties change.”

“Under your guidance, Uchiha Shisui has worked hard to practice, and his overall strength has been greatly improved, and he has been rewarded – the Immortal Human Body!”

Under Mu Yue’s guidance, Zhishui understood that the village’s enemies were not necessarily other big countries, but could also be within the village. People who spoke righteously about the will of fire might not necessarily act in accordance with the will of fire.

Obito got rid of the title of being the weakest person in the ninja school, and Metkai became a master of physical skills even earlier…

- Description from novelbuddy

A man reincarnates in the body of a boy who suffered a tragedy, only to realize that he is in the world of My Hero Academia. What's even stranger is that his quirk seems to have the abilities of Nen and Haki.