In the wake of a third world war which left Japan in ruins, an organization known as Vischio seized control of Tokyo and renamed it Toshima. Taking place in its back alleys are battle games known as Igura, overseen by the Vischio, in which contestants battle and bathe in each other's blood to earn the chance to go up against its tournament's king, Il-re. Igura is not the only fighting tournament around; Bl@ster is a similar yet vastly different game since it prohibits murder and the use of weapons. The only way to win is by knocking out the opponent. Akira, a young man isolated from his family, is known to be undefeatable at Bl@ster. However, his life on the top is shattered when he is accused of murder. Unable to prove his own innocence, all hope is seemingly lost... that is until a mysterious woman named Emma appears and offers him a chance. Now, to regain his freedom, Akira must participate in Igura and ultimately defeat Il-re.

In a special jurisdiction area built in Tokyo Bay commonly known as the 24th Ward, the population enjoys a very safe life thanks to the Hazard Cast—a surveillance system that predicts accidents and assists victims immediately. However, the system cannot foresee the exact nature of these accidents nor prevent them from happening. Ran Akagi, Kouki Suidou, and Shuuta Aoi—a trio of friends nicknamed RGB due to their hair color—experienced the tragic nature of these limitations when Suidou's sister Asami passed away in a fire at her high school. A year later, Shuuta still blames himself for failing to save Asami, while Ran pursues his dream to become a famous street artist, and Kouki works in the Hazard Cast intervention unit. After the RGB trio reunites at a commemoration for the victims of the school fire, each of them receives a mysterious phone call. Bewildered to hear Asami's voice, the three friends are shown images of the future and asked to choose between two grim alternatives. Refusing to be bound by predetermined outcomes, the three tackle this troubling event head-on, marking the beginning of a series of cruel dilemmas that they will have to overcome in order to protect the 24th Ward and its people.

Subaru Sumeragi is the 13th head of the Sumeragi Clan and a most powerful onmyouji. Subaru is hired to exorcise a construction site, but his employer mysteriously died. The only suspect is a man who repeatedly walks away from situations in which he should have died. Then Subaru meets a young woman intent upon cursing the man, saying that he killed her brother. Subaru must figure out how his employer died and fight the evil spirits that are protecting the man with the help of his friend and twin sister, Seishirou Sakurazuka and Hokuto Sumeragi. (Source: ANN)

Onmyoudou magic was once a powerful technique used by the Japanese during the second World War in order for them to gain the upper hand and establish their nation as a formidable force. But Japan was quickly defeated after the revered onmyouji Yakou Tsuchimikado caused the Great Spiritual Disaster, an event which plagues Tokyo to this very day. As a result of this mishap, the Onmyou Agency was established in order to exorcise further spiritual disasters and combat the demons that would make their way into the world. Now, Onmyoudou has become far more modern, simplified, and refined for use in a wide variety of applications such as medicine and technology. However, not everyone is able to utilize the magic, as is the case with Harutora, a member of the Tsuchimikado's branch family. Despite an old promise to protect Natsume, the heir of the Tsuchimikado's main family and Yakou's supposed reincarnation, as her familiar, Harutora has no talent and chooses to live a normal life instead. But when a prominent member of the Onmyou Agency attempts to recreate the same experiment which led to Japan's downfall, he decides to make good on his word and fight by Natsume's side.