Accel World, Vol. 2 (light novel): The Red Storm Princess

Since meeting Kuroyukihime, an avatar in a virtual world, Haruyuki has managed to grow up a bit, but in the Accelerated World, he must now subjugate a cursed piece of enhanced armament which is polluting the minds of the duel avatars that don it and only Silver Crow, the sole duel avatar with the power of flight, can apprehend the relic.