Yakumo Amagiri (雨霧八雲, Amagiri Yakumo), born Takehito Isegawa (伊勢川尊人 Isegawa Takehito), is the Artificial Island's resident rumored serial killer and known to its residents as the urban legend 'Killer Ghoul'.
Though the Islands' residents gave him the 'Killer Ghoul' moniker, less than half of the population are certain that he actually exists and none know the reason for why he kills. Eyewitness descriptions of him have ranged from a little girl in gothic lolita fashion to a giant over two meters tall, further legendizing him.
Yakumo has white hair and white clothes, the latter of which are often stained with blood. A chain of sorts is looped around the frilly collar of his coat.
Yakumo thinks at a much higher speed than most people (Gitarin describes this as him having a 'high clock rate'), meaning that thought processes which take several minutes for one person take a few seconds for him.
As a result, he is incredibly introspective to the point where his thoughts can utterly overwhelm him. His awareness of his 'self' and how others see him has led him to be incredibly self-conscious of his behavior and possible courses of action available to him. Above all else, he is obsessed with the idea of normalcy, constantly reaffirming that he is 'normal' and that everything he does is not 'abnormal'; that he is aware that he is self-aware, then, is 'proof' of his normalcy.
While Yakumo blames the nature of the Island as the reason he kills people at all, the reasons he gives for his quotidian murders are utterly whimsical: he kills because the sky is blue; because it is raining; because it is nighttime. The reasons serve more as a reminder to himself that he is committing the nauseating act of murder – though, over time, he has ceased to feel guilt over his actions.
In blaming the Island as the cause for his murders, in the islanders nicknaming him 'Killer Ghoul', and in his desperate desire to be and be perceived as a normal human, Yakumo has come to call the identity of the Killer Ghoul and Yakumo Amagiri as a "killer's mask". As a mask, the identity protects the "real him" underneath, and thus can simply be 'removed' once he leaves the Island. However, his self-conscious behavior leads him to constantly grapple with the possibility that the 'mask' may be the real him and that it may never have existed in the first place.
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Yakumo's 'high clock rate' means that time occasionally appears to 'slow down' for him. This, coupled with his acrobatic prowess, leads him to be extremely deft at avoiding the blows of others.
He is versed in a variety of dancing styles – including breakdancing, ballroom dancing, tap dancing, traditional Japanese dance, and Noh among others – and once won a nationwide dance competiti
Article to be expanded.