Suda consistently characterizes Shiroyabu as an immature, ineffective child, and other characters, particularly Kuroyanagi Shinko, seem to understand him as such. In “new world order,” he is introduced failing to solve the case of Miru’s murder and negligently allows the deliverymen to kill his partner. In the third case, “boys don’t cry,” in November, Shiroyabu struggles with impulsive spending. “Why can’t I control myself?” he says. Kiryu, Kosaka, and Kurumizawa coordinate to send a series of hitmen after Shiroyabu. While their ostensive goal is to eliminate the threat Shimohira’s son might pose, Kosaka and Kurumizawa seemingly intend to death-file him as a way of wasting his potential or interfering with the HC Unit.
The plot succeeds: with their prodding, Shiroyabu embarks on a rampage of rape and murder that ends with him death-filing, literally metamorphosing into an inhuman monster who not only still cannot control himself but increasingly cannot understand his surroundings. (He also loses his pretty white hair!) Initially Shiroyabu does appear to achieve success in his war against Kamui, killing Kurumizawa and Uehara. As we have seen, though, Uehara is fine, so Shiroyabu can’t even do that right.
In his final appearance in “electride,” belying his superhuman death-filed powers, Shiroyabu cannot recognize that Mayor Mikoshiba has been assassinated and then realizes is as mistaken to believe he defeated Kurumizawa as he is to believe he defeated Uehara. Dismissive, Kurumizawa tells him, “You killed me, I was killed, none of that really means anything.”
In this climactic scene, Shiroyabu seems more childish, whiny, and pitiful than anything:
KUROYANAGI: “You all just wanna do things as easily as possible and have others think for you. Get your shit together.”
SHIROYABU: “Kuro-san, I’m tired.”
KUROYANAGI: “And fucking spoiled, too.”
SHIROYABU: “I’m tired. Please kill me.”