Dead End Demonics: The First Returner

Read Dead End Demonics: The First Returner / Dead End Demonics : The First Returnee / デッドエンド・デモニクス〜始まりの帰還者〜
Eight years ago, an unknown disaster known as the “Demon World Transformation” struck the world.
It was a calamity of despair that sealed off pockets of reality, repainting them into nightmares.
If you couldn’t survive, only a cruel death awaited you—
In this completely changed world lived Yugo Fushimi, a young man who kept his outings to a bare minimum, shuttling only between his home and his workplace.
Timid, kind, and sensitive to the pain of others…
But because he was always sleep-deprived and habitually late, his colleagues mocked him daily as a “slow-witted pushover” and a “gloomy shut-in.”
Then one day, Yugo was dragged to a drinking party against his will—
And there, he witnessed the nightmare of the “Demon World Transformation” with his own eyes.
The city overrun. People screaming. His colleagues cut down.
The space had turned into a Demon World, overflowing with grotesque enemies. Survival seemed hopeless…
But then.
There was one man.
As if recalling a distant memory, he gripped his weapon—