7th Demon Prince Jilbagias' Chronicle of Demon Kingdom Toppling - Chapter 89.1 - Price of Sin

Working in a big factory for several years, Wang An, who was prematurely aging, accidentally obtained a cheat that can earn experience. The improvement of his skills brought him unexpected surprises.

It turns out that some things are not just legends.

Lightness kung fu can really make people walk on the snow without a trace, and fly over the walls.

Vajra is not broken, it can indeed produce the power of vajra, and become the body of vajra, invulnerable to swords and guns.

Congenital qi, grasping iron into mud

 …

Brushing experience does not rely on simple repetition, but requires continuous learning, summarization, and comprehension.

- Description from novelbuddy

Waking up, Kim Hajin finds himself in a familiar world but an unfamiliar body.

Who says I am a worthless student, the pretty Alliance Leader is within my grasp.

Who says I am a single man, a harem of huge numbers waits upon me.

Watch how the strongest senior high school student in history, Li Fan, turns over the city upside down, becoming a hero unparalleled under the heavens!

My wife is the martial alliance leader, and I am the strongest senior high school student, Li Fan! I’m waiting for all of you to drop in to discuss the rules of Jianghu!

- Description from Novelupdates

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.