A Guide for Background Characters to Survive in a Manga - Chapter 43

[You have entered the dungeon at Gwachun Station’s 1st Exit.] When former high school student Kang Woojin finds himself returned back to Earth after being forcibly summoned to a foreign planet for 20 years, he soon finds that Earth is not the same, normal place as he once remembered it to be.

Are you humiliated by being attacked?

Are you sorrowful to be a stepping stone?

As a cannon fodder hanging in two episodes, are you unwilling?

Don’t worry, I am here!

As the only system supplier of All Heavens and Myriad Realms System Shop, I can make a variety of portable systems for you, and let you reach the peak of your life!

Boy, it’s time to raise your eyebrows!

Boy, it’s time to counter-attack!

- Description from Novelupdates

When a Demonic Assault occurs, most people stuck inside of a Fracture end up hiding inside of a bunker in the hopes that they don’t end up killed by a demon.

Others might even hope for the slightest possible chance at signing a contract with a spirit and becoming a Guardian.

So when Scarlet was caught in a Fracture, the last thing she expected was to become a demon herself.

Exactly two centuries ago, humanity was struck with their very first Demonic Assault.

The skies above the capital of the US, shattering as if made of glass; demons of all kinds appearing out of nowhere; and no way to effectively stop them before the end of the Assault.

On the brink of devastation, some of the humans managed to find themselves offered a contract whilst inside of a Fracture. One bringing a chance at power, fame, and fortune.

Now, long after every nation of the world joined together to form the Terran Republic, Scarlet finds herself stuck trying to find a university from the Republic’s capital that will accept someone from a lower tier city into their midst.

But, as if that wasn’t already enough trouble for one person to bear, she somehow ends up stuck in one of the Fractures of a Demonic Assault while visiting her father figure’s company building.

However, she doesn't perish in the darkness and instead awakens her dormant bloodline as a noble demon.

A Blood Lycan.

Turns out she had been a demon all along and had been born for the apocalypse.

He was on his way to buy some beer to celebrate his acceptance as a civil servant when he was suddenly isekai’d by truck-kun.