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The three-year-old 'youngest son' of the Midarezaki family. He is a biological weapon made from the flesh of Enka that bears the name of 'The Black Thirteenth' (黒の十三番 ,Kuro no Jyūsanban?). Three years ago, he destroyed the laboratory where he was made and ran away, and it seems that he is currently suppressing his past memories. According to his creator, he was once also referred to as 'Robes'. In a speech to Yūka, he tells her that every member of the Midarezaki family is between 'Heaven and Hell', not being able to tread in either. He enjoys watching television and seems to be the only one that can eat Kyōka meals (but this could be due to the fact he doesn't have a stomach or taste buds). He has a brother that has been dubbed as Dekamelon by Kyōka, almost a green version of Hyoka with a running gag that something happens right before he can say his real name. Hyōka has feelings for Takanashi Kiriko, which were later revealed to be mutual but she doesn't want for their relationship to start till after she has found herself.