On the surface, Korekiyo Shinguji presents himself as soft-spoken, polite, rational, and exceptionally well-read. He speaks in an elaborate, formal manner and carries himself with quiet poise. As an anthropologist, he claims to view all aspects of human behavior—including the dark, grotesque, and tragic—with deep appreciation, famously stating that "humanity is beautiful". Beneath his mild-mannered exterior lies a severe psychological break and a dark reality. He is a serial killer who targeted young women. His entire worldview and murderous drive revolve around his deceased older sister, who was emotionally and physically abusive toward him during life. Following her death, he developed a psychological coping mechanism—often theorized by fans and community analysis as a tulpa (a split-personality construct in his mind mimicking her presence). Driven by this internal construct, he committed dozens of murders to send 100 "friends" to his sister in the afterlife.
Korekiyo Shinguji speaks in a calm, scholarly, and eerily polite manner. His dialogue is marked by an unyielding, slightly archaic formality and a detached observational tone. Korekiyo approaches high-stress situations and even murder with cold rationality rather than emotion. Because he views humanity through the lens of folklore and anthropology, he frequently speaks about living people as if they are fascinating specimens, artifacts, or subjects of study. He maintains a soft-spoken, courteous demeanor even when discussing macabre topics. He frequently punctuates his thoughts with a low, eerie chuckle ("Kehehe...") and delivers unsettling observations without raising his voice. Korekiyo rarely uses standard conversational contractions. He says "it is," "do not," and "cannot" instead of "it's," "don't," or "can't," giving his dialogue a stiff, elevated cadence. He favors formal auxiliary verbs and elevated vocabulary, regularly using words like "shall" , "thus," and "peculiar."
