Naruto System in One Piece - Chapter 524: Battle Against Sasori

A magical ‘universal toolbox’ that allowed Joga to step into the arms industry.

The strangeness of the world made Joga gradually change his goals…

“Sir, how did you get to this point?”

“I don’t know. At first, I just wanted to make some money, buy a house, and marry a wife. But slowly, as more and more people appeared around me, my goals began to change. ”

“Then what is your goal now?”

“Now I just want to retire in peace with my guys, really!”

- Description from novelbuddy

The first time they met they had battled fiercely, just for a mere bunch of herbs. She needed it to save people, and he wanted to use it to save his own life.

It was a time where demons roamed the earth and chaos reigned. The story took place in Luoyang, the legendary capital of the times. During the night, one could find people holding on to their food with dear lives as they faced off against stray dogs, people with weapons in hand vowing to fight against Fate to their very last breath. There was bloodshed everywhere as some died meaningless deaths, while the strong tyrannized the weak and the truth was frequently hidden. Some of the citizens had completely lost their mind, while some died on their travels. Most importantly, the words of a certain youth caused much panic in the human world. It was a time of little warmth as nights in the capital were frequently accompanied by gusts of wind and rain, and it would be covered with snow during winter. Such were the days…

- Description from Novelupdates

Among the demons, the supreme ones are called “Great Saints.”

A young man leaves his mountain village and travels around the world. By unceasing efforts, he finally becomes a legend of the age.

- Description from Novelupdates