City of Sin - Book 1, Chapter 5

Ryan «Quicksave» Romano is an eccentric adventurer with a strange power: he can create a save-point in time and redo his life whenever he dies. Arriving in New Rome, the glitzy capital of sin of a rebuilding Europe, he finds the city torn between mega-corporations, sponsored heroes, superpowered criminals, and true monsters. It’s a time of chaos, where potions can grant the power to rule the world and dangers lurk everywhere.

What is the experience like after transmigrating into the novel’s foreordained miserable cannon fodder?

Su Zui, who had only ever treated other people as cannon fodder, expresses——

Your father is still your father.

Winning just by laying down, system silently gave his family’s host a call: Papa 666.

Boss: Be good. A single parent family isn’t good for the child. Call me papa number two.

System: ???

Even though the roles assigned are all definitely touching and inevitably miserable cannon fodder, this does not hinder Su Zui’s path on oppressing main leads to the point they question their life.

- Description from Novelupdates

The world was once at war with 10 alternate worlds. This was known as the Concept War and our world won 60 years ago. All of this was concealed so no normal people are aware of this fact in the current time.

After the death of his grandfather, the high-school student Sayama Mikoto is suddenly summoned by the giant corporation IAI. He learns this world is headed for destruction due to the acceleration of the Minus Concepts. To prevent this, negotiations must be undertaken with the survivors of the other parallel worlds so their 10 concepts can be released.

And so Sayama is caught up in the final battle to clean up after the Concept War which left behind so much enmity.

Chen Rui, an otaku from earth, is reborn into a human body in another world, who falls into the legendary evil, brutal world of the devil called Mozu where humans are treated as food. He has to survive while facing horrors of the devil, violent dragons and a variety of power enemies depending on a strange super system chip and his wits. Surrounded by Devil’s beauties such as black-bellied lolita princess, cold queens, violent dragons, charming poisonous devils …

Wanting to live in the Devil’s world is hard! Wanting to live in the Devil’s world as a human is harder! Wanting a human to be the devil’s son-in-law is hardest!

Let us see how a small otaku uses power and strategy step by step starting from an ordinary human to writing a legend as the devil’s greatest son-in-law.

- Description from Novelupdates