Atsushi Nakajima vs. Kōyō Ozaki

Atsushi Nakajima vs. Kōyō Ozaki is a battle fought between Armed Detective Agency member Atsushi Nakajima and Port Mafia executive Kōyō Ozaki before the onset of the three-way gifted organizational conflict among the Agency, the Mafia, and the Guild.

It happened somewhere in Yokohama's central square shortly after Kyōka Izumi's first Agency mission at the Yokohama District Court.

Prologue
Atsushi accompanies Kyōka to her first mission from the Agency that requires her to deliver some evidence to a court judge. After she accidentally electrocuted and angered the judge upon her survival instincts in trying to accomplish her mission, Atsushi tries to cheer her up and treats her to some crêpe.

He notices her phone with her and wonders if they can soon figure out the mystery behind Demon Snow, upon which they can perhaps put it to good use. Kyōka shuns such idea and implies that it must not be activated ever again. The phone suddenly rings, and a voice commands Demon Snow to punish those who delude Kyōka with lies.

Battle
Demon Snow materializes and stabs Atsushi from behind. Afterwards, Port Mafia executive Kōyō, the voice responsible for the attack, arrives before Kyōka and expresses her concern for the girl. As she stomps on Atsushi whom she regards as vermin, Kōyō assures that she has come to save Kyōka. Atsushi quips that Kyōka will never return to the Mafia, as her ability shall be put to use in the Agency.

At such remark, Kōyō sheds some tears and regrets having waited for Ōgai Mori's permission to fetch Kyōka back to the Mafia. She then embraces the latter whom she claims has been beguiled and lured into the light, warning her that the Agency shall exploit her ability for their profit one way or another.

Kōyō declares that she shall dispose of anyone who plans on utilizing Kyōka and her ability for their own purposes. Atsushi quickly activates his ability, only to be stabbed instantly by Kōyō's Golden Demon. As he is pinned against the wall, Kōyō prepares to finish him off. Kyōka pleads her to stop, to which Kōyō tells her that Mori has ordered to kill Atsushi and everyone in the Agency, save for Kyōka out of Kōyō's personal request.

Once more, Kōyō asks Kyōka to come back with her to the Mafia. She also reminds her that she is a flower of darkness meant to live in the dark, but Kyōka refuses to believe her. Under the thought that he has blinded her with the light, Kōyō turns to Atsushi and prepares to kill him with her katana in order to force Kyōka in defecting from the Agency upon his death.

Aftermath
To spare Atsushi's life, Kyōka soon agrees to come with Kōyō back to the Mafia, compelling the executive to leave Atsushi behind. This, however, turns out to be a feint by Kyōka, and she puts up a fight against Kōyō herself.