Allen Walker, an Exorcist with a cursed arm, must confront the Millennium Earl and his Akuma, demonic weapons created from the souls of the grieving, to prevent humanity's destruction. The Black Order, a group of Exorcists wielding Innocence, fights against the Earl's forces. Allen's own Innocence, a powerful anti-demon weapon embedded in his left arm, is both his greatest asset and a constant reminder of his mysterious past and the potential for his own corruption.

D.Grayman is widely recognized for its intricate world-building and compelling character arcs, particularly focusing on the protagonist Allen Walker's internal struggles and his fight against the demonic Akuma. The series is praised for its unique blend of gothic aesthetics, supernatural action, and exploration of complex moral themes, drawing readers into a dark fantasy world. While the manga's publication schedule has faced interruptions, its dedicated fanbase continues to appreciate the depth of its narrative and the emotional weight of its conflicts. The visual style is often highlighted for its distinctive character designs and atmospheric paneling, contributing to its enduring appeal.