D.Gray-man, Vol. 20

Allen and his fellow Exorcist, the formidable and misanthropic Yu Kanda, discover the latter's background—including his true nature and purpose—in visions that flash back to his childhood. Yu's memories of this time have long been suppressed, and it seems for good reason. They not only involve Yu but another child named Alma, and expose how desperate certain factions within the Black Order were to counter the threat posed by the akuma and their master, the Millennium Earl!