D. Gray-man

D.Gray-man is the story of Allen Walker, who roams a fictional 19th century Earth in search of Innocence, a mysterious substance used to fight demons called akuma. Allen and the other exorcists must fight for their lives on the ark created by the Millennium Earl. But even as the ark around them is disintegrating, the earl hatches a new plan, and this one requires him to retrieve the Egg from the Black Order. Can the exorcists survive his next attack?!