DB: Legendary Super Saiyan Bloodline at the Start - Chapter 41: Another Little Bug

Death is sometimes not the end!
Dead prison!
This is a magical prison. It has the ability to draw the souls of the dead people of the world, and it also enables people to gain the ability of the souls of the dead.
When Qin Song woke up, he was shocked to find that he had come to the world of One Piece, and even more surprised that he found a prison in his body…..

- Description from Uukanshu

Perhaps it is the choice of fate. As a senior otaku, Qian Lingfeng got the “steel shell system”. However, when he swept the world with the system, became a local rich man, made all kinds of beautiful women, opened a harem, and realized the ultimate fantasy of thousands of otaku, he found that things seemed far from simple!
When the end comes, biochemical zombies suddenly come down, fierce beasts are in power, bloodthirsty zerg roam to kill the world, and human lives are comparable to dirt. Where will weak human beings go in this world? Is humanity going to be extinct? Or … can an otaku save the fate of the human race?

- Description from Novelupdates

16 years old-- most boys would be falling in love, as their hormones all rise to unprecedented levels. Most boys at Riley's age would have dreams; dreams that will slowly grow into passion. Riley, however, at age 16... killed the world's number 1 superhero.

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