In the year 2109 the most impressive technological advancement done in the field of video games has been made, that is the invention of virtual reality massively-multiplayer online games.

It was made possible due to the gaming console manufacturer PoCo they invented a human sized console capable of "transfering a person's consciousness into a video game".

However in reality, what the company did was create a machine that would transport the user to a parallel universe where the elements of an rpg are a common thing.

In the midst of its popularity a huge electrical surge suddenly occured worldwide rendering the users of the machine to be stuck in their own respective games.

The most popular game then was FeudalQuest XV which have the usual cliche's of an rpg.

More than a million of players are online during the electrical surge, including the 17 year old boy Isayama Issei who was only trying the console out of curiosity in a public mall.