MTL - Acting Like a Cannon Fodder is the Best Life - Chapter 54

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

Calamity descends upon a a tranquil world in the black of night, transforming it into a death game! This a a true apocalypse, but this is not the end of humanity!

- Description from Novelupdates

Year 2022, December the 1st. This was the day it all began.

Labyrinths had started forming all around the world, hundreds and thousands of people lost their lives as casualties.

Mutations followed after, occurring amongst the people, they began awakening super powers, the same for animals.

However these mutations brought along a virus. It quickly spread amongst the dead as they began to rise. Humanity had begun its fall.

Gray who had given up all hopes of living life, was granted a system with a special ability. On the very same day, of the outbreak, he was consumed by a labyrinth.

By the time he had gotten out, a week had passed. It was hell all around. A virus had broken out from the mutations, the dead were walking and spreading this virus.

However this was only the beginning.

Over time the mutations began to evolve and people learnt that the through the cultivation of their powers, they could improve their abilities.