Accel World Novel Volume 21 is written by Reki Kawahara.

In the Unlimited Neutral Field, members of the new Black Legion fall victim to a surprise attack at the hands of Orchid Oracle, a Burst Linker long considered lost to Brain Burst. Thinking quickly, Silver Crow retreats to the Highest Level with Metatron in an attempt to grasp hold of the situation, but there they are greeted by a brand-new adversary! Snow Fairy, an F-Type avatar of the White Legion unleashes her devastating attack and severs the link between them! It's up to Kuroyukihime and Niko to save their Legion members!