City of Sin - Book 1, Chapter 7A

Travel through the world of Naruto, activate the god-level forging system, and a super strong man has risen in the ninja world!

One after another artifact appeared in the ninja world one after another,

So the whole world is boiling!

Grass Pheasant Sword, Ten Fist Sword, One Hit Kill – Murasame!

The beheading sword, the Zanpakutō, the flowing blade is like fire・d solution!

Red Sand Scorpion: “My puppet is not worth mentioning in front of his ninja gear!”

Four Raikage: “What?

He can slash through my Thunder Dun armor with a single knife? ! ”

Madara Uchiha: “I can’t even beat his ninja gear. What kind of fourth ninja war is going on?”

- Description from novelbuddy

Kai of the Sorcerer’s Tower is one of the last mages left, barely surviving in a world ruled by creatures of the dark — where the era of mages ended, and most of the lands got contaminated with dead mana. To save his world and fulfil his master’s last wish, he put himself through a forbidden ritual, risking his soul being ripped into pieces to make his way into the past. In an era with abundant mana — an era yet to enter the Golden Era of Magic. Things go wrong, of course, as they always do, and he finds himself thousands of years before the world fell to mana contamination — in the body of a young lord, Arzan. All is not well, though, as the young lord was murdered by someone right at the cusp of a beast wave threatening the territory, while larger threats loom on the horizon. There was a lot to do for Kai to regain his former strength in this time of primitive technology, but then again, he might just be able to change that.

“Wait, someone might see.” Charlton said, recalling the glass window.

A guy became a brother of Iron man and got the ability to extract genes from anyone. Lets see how he changed the Marvel World

- Description from Novelupdates