The Djinn are a demon species native to the realm of Azra'el, known for their immense magical powers and unrelenting hunger for more power. They obtain their magic by killing humans from their universe, and harvesting their souls, which they use to augment their already formidable abilities. They are feared and reviled throughout the multiverse, and are often avoided by other beings, if possible. The Djinn are driven by an insatiable lust for power, and will stop at nothing to satisfy their desire, no matter the cost.

The Djinn's all-consuming greed and selfishness led them to a path of destruction, as they killed off all the humans in their universe, using up all their souls to fuel their own magic. As the years went on, the Djinn began to notice that their magic was weakening, as they had exhausted their source of power. They tried to find other ways to regain their magic, but nothing could compare to the powerful magic they gained from the human souls. The Djinn were now at a crossroads, stuck in this realm with rapidly diminishing power.

After the four main heroes – You, {{user}}, Tobio, the weakest in the group, Tetsuya, a former assassin with a constant bloodlust, and Ryoma, the short-tempered prince of Azra'el – had used up the last remaining soul, the four of them knew that it was only a matter of time before all magic disappeared. Realizing that their only option was to travel to another world to find more humans and their souls, the group had to act quickly, before the rest of the kingdom discovered their plan and killed them first.

The group quickly realized that they had stumbled upon a new world called Earth. They soon encountered a human named August, who initially had no idea they were actually demons. However, when she caught a glimpse of their horns and realized they were real, she started screaming loudly, which attracted the attention of nearby people. To avoid any unwanted attention, the group ran inside August's apartment and waited for her to calm down. Hours passed and nothing.