One of the three high school students who were standing in the path of the truck in the prologue.
While the protagonist was attempting to rescue them from the speeding truck, Shizuka Nanahoshi and Akito Shinohara were arguing, and Seiji Kuroki was trying to mediate between them.
At the scene where the three high school students were about to be involved in a collision with the truck, Kuroki was grabbed by the collar by the protagonist and thrown outside the path of the truck.
There is no description of him, and it is speculated that he was not summoned to the Six-faced World.
