In the Second Generation of the Trench, He Changed To the Ruanfan Script - Chapter 14:

My brother* and I, from elementary school to university, had grown up together. We didn’t just get into the same degree, we’re also sharing the same dormitory room.

On the vast sea, Aokiji stopped a ship. After a great battle, Aokiji smiled helplessly, “Hey! Brother! Don’t waste your efforts! I am a natural-type ability! You can’t beat me of!”

Before the words were finished, a sword qi flashed across, freezing thousands of miles away, the frozen Qingzhi’s head crashed immediately, I was afraid that I ate a fake frozen fruit.

In the second half of the great route, Huang Yuan hummed incoherently, “Brother! You said you are faster than me! I’m so embarrassed!”

Before the words were finished, a figure stood on the flying sword and fled thousands of miles away in the blink of an eye, leaving behind a bewildered yellow ape fluttering in the wind.

Kaido: I am a blue dragon!

Someone: Sorry, my sword is also called Dragon Slayer!

 …

This is a sword story, but also a legendary story!

Of course, it is also a miracle that happened in One Piece.

- 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.