"Azrael's EDGE" is a manga series that blends elements of action, fantasy, and psychological drama. The story is set in a dystopian world where humanity is under constant threat from monstrous entities known as "Demons." These creatures emerge from a mysterious void called the "Edge," which serves as a gateway between dimensions. The narrative centers on a group of individuals known as "Edge Keepers," who are tasked with defending humanity by wielding powerful weapons called "Edges." These weapons are imbued with unique abilities but come at a cost, as they gradually corrupt the users' minds and bodies.

The protagonist, Ryo Asuka, is a young Edge Keeper who wields the titular Azrael's Edge, a weapon of immense power tied to the angel of death. Ryo struggles with the moral and psychological toll of using such a destructive force, as it amplifies his inner darkness and threatens to consume him. Alongside Ryo is a diverse cast of characters, each with their own Edges and personal struggles. These include Aya Kisaragi, a skilled and pragmatic fighter who serves as Ryo's foil, and Kaito Shindou, a former Edge Keeper haunted by past failures. The group is united under the organization known as the "Edge Division," which oversees their missions and attempts to maintain order in a chaotic world.

The plot unfolds through a series of missions against increasingly powerful Demons, interspersed with flashbacks and character-driven arcs that explore the origins of the Edges and the Edge Keepers' personal histories. Themes of sacrifice, identity, and the cost of power are central to the narrative, as the characters grapple with the consequences of their choices and the inevitable corruption brought on by their weapons. The story also delves into the nature of the Edge itself, revealing its connection to a larger, more sinister force that threatens not only humanity but the fabric of reality.

As the series progresses, alliances are tested, and the line between hero and villain becomes increasingly blurred. The Edge Keepers must confront not only external threats but also their own inner demons, leading to moments of intense psychological and emotional conflict. The narrative builds toward a climactic confrontation with the true source of the Demons, culminating in a resolution that challenges the characters' understanding of their world and their place within it.