Winter, 12th December 20xx. Under the dark, cold sky where snow falling gently but not with the chaos accompanying along the way. The Scream, the cry and the trace of blood could be found everywhere. People at the time tried their best to survive the calamity raining upon them. Among them, there stood a man in his early 20s. Just like any normal human would react, he looked around, with his shocked eyes.

「"What the hell is this...?"」

With bare eyes, he witnessed hundreds of people shredded to pieces by unknown creatures. Some of them he recognised, similar to raptors. Some other as something he ever seen in certain illustration sheets—black faced entity with large horns and long tail just like a devil. The rest he had never seen before. Hence, he didn't even know how to describe their shape.

He started to run, tried to avoid the devil-like entity's strike, reminiscing the so-far events.

The sudden popped up window, the calamity afterwards, the monsters that he strangely felt familiar to lot of them, the city as the background, even the current date... In the next second, it felt like revelation just hit the back of his head. He recalled something. A certain title on the popped up window he saw 15 minutes ago.

[Welcome to 「World Game Invasion : Grey Fate」 dear Esper #467007600]

World Game Invasion...

「"this is really... my own story?"」

「"How absurd this world can be?!"」