Accel World

Ruka and Mana introduce Kuroyukihime to their master, Crimson King, an old acquaintance of Kuroyukihime's. According to Crimson King, a powerful Enemy is preventing them from hunting down regular Enemy units within Okinawa's field with no limits. To make matters even worse, that same Enemy is under the control of a Burst Linker calling himself Sulfur Pot, who attacks Kuroyukihime and others.