Apocalypse: I Have A Multiplier System - Chapter 471: P280 Serum

Step inside if you dare, but be warned—this is no ordinary shop. Those who enter never leave the same… if they leave at all. A sinister force lurks within, fueled by a dark past and a thirst for revenge. The price? Twelve lives for twelve sins. As officials race to put an end to the bloodshed, the shop’s deadly grip tightens, claiming innocent victims one by one. Will anyone uncover the truth before it's too late? If you crave spine-tingling horror, heart-pounding thrills, and a mystery that refuses to stay buried, this book will haunt you long after the last page.

This world is Heaven.

Because this world has everything you dream of, everything you wish for.

This world is Hell.

Because everyone in this world are parts of a never-ending massacre.

Are you fighting to survive, or fighting to come home?

- Description from Novelupdates

A girl who calls herself a demon appeared before a timid student named Fumio Kijima. The girl claims to be a campaign girl from the demon world and she gives him the ability to “summon a room” from nothing but thin air.

At first he doesn’t abuse his power and uses it as a convenient ability in his every day life. But one day he is bullied by his classmates under a false pretext and is made to suffer. In the past he would have wallowed in misery and cried himself to sleep, but now he had a power to call upon.

“I will make them regret it!”

Using his powers to summon his “room”, he begins his era of confinement and brainwashing to achieve his goals.

I had transmigrated into my favorite game, as an extra who died before the story even began.In a world where Sigils dictate power, I found myself in the body of a boy who had already died on the battlefield.Yet, as I drew breath in his place, his Sigil changed. A power never meant for him, never meant for me.Kidnapped by a shadow organization that didn't exist in the game, I spent three years in the dark, forced to learn under a so-called teacher.I move forward, not as the extra I was meant to be, but as one who chooses their own path. A path to supremacy.Yet the deeper I walk, the more I realize… this world holds secrets that game had never shown.-----------------Additional tags:[Sword Companion], [Hidden Identity], [Artifact Power], [Slow Reveal], [Secret Society], [Survival]