D.Gray-man centers around Allen Walker, who is gifted with the ability to control a weaponized form of a divine substance, called Innocence, and becomes an Exorcist of the Black Order. This secretive organization aims to stop the plan set in motion by the Millennium Earl to destroy all life on Earth. Because of the Akuma's ability to wear a human's skin, they are nearly undetectable by humans. Allen proves to be a powerful asset as his 'cursed' left eye is able to detect the Akuma. Soon, this battle nearly turns into a race to collect the 109 Innocence fragments, scattered since the Great Flood of Noah, as the search to find the most powerful Innocence the 'Great Heart' ensues.