D.Gray-man, Vol. 17

A cursed teenage boy saves mankind one soul at a time. An experimental virus is turning members of the Black Order into zombies! Even Count Krory is infected, driving him to attack Allen and Lavi. It's up to Komui, creator of the virus, to deal with this disaster, but though he knows how to stop it he literally doesn't know where to start. Can he figure it out while also contending with a vengeful spirit eager to see the virus complete its rampage?