A huge castle made of stone and steel floating in an endless sky. That was all this world was.

It took a various group of craftsmen one month to survey the place; the diameter of the base floor was about 10 kilometers, large enough to fit the entirety of Setagaya-ku within. Above, there were 100 floors stacking straight upwards; its sheer size was unbelievable. It was impossible to even guess how much data it consisted of.

Inside, there were a couple of large cities along with countless small scale towns and villages, forests and plains, and even lakes. Only one stairway linked each floor to another, and the stairways existed in dungeons where large numbers of monsters roamed; so discovering and getting through was no easy matter. However, once someone made a breakthrough and arrived at a city of the upper floor, the teleport gates there and of every cities in the lower floors would be connected making it possible for anyone to move freely through these levels.

It's been two decades since the game of death was played by 10,000 players only which about 6,000 survived and the other 4,000 have met their fate in the game.

Twenty years later, it makes a comeback. More than just the nation of Japan can join, more have improved and more have worsened as of its current run.

The name of the castle was Aincrad, a world of battles with swords that continued floating and had engulfed approximately ten million people. Otherwise known as...

Sword Art Online.

Disclaimer: I do not own Sword Art Online or any of its characters. The original story and universe is originally from A1 Pictures, abec and Aniplex, created by Reki Kawahara. Please support the official release (and the abridged series!).