Versus

Versus is the «Sword Art Online» and «Accel World» crossover published on December 10, 2011 in Volume 10 Chapter 3 of Accel World. It was also adapted into one of the tracks of Accel World + Sword Art Online Drama CD.

Summary
Kirito tests the «4th-Generation FullDive Experimental Unit» and enters the Umesato Middle School Local Network by accident. Haruyuki Arita reflexively attacks him and they fight. Ultimately the battle is stopped before either lands the decisive blow, and both think that the other would have won. After the fight Kirito talks about Humanity evolving wings, and Haruyuki talks to Kuroyukihime about the color black being the warmest color.