D.Gray-Man

Akuma are monsters created when grieving loved ones mistakenly bring dead souls back into the living world, and they serve the Millenium Earl in his effort to destroy humanity. Allen Walker has fought them since childhood, wielding an anti-Akuma weapon in his left arm and an eye that can see the souls trapped within them. Allen is among the few people who carry Innocence, a substance that lets its wielders kill Akuma and oppose the Earl. He joins the Black Priest Organization as an Exorcist, setting out alongside other Exorcists to stop the Earl’s attempts to annihilate the human race.