Chiri Kitsu is a student in class 2-He, known for her methodical and precise nature. She exhibits obsessive-compulsive tendencies, demanding strict adherence to order, categorization, and literal interpretation of rules. Deviations from precision trigger extreme distress and provoke violent reactions. Her pursuit of exactitude leads classmates to mistakenly identify her as the class representative despite her lacking the official title.

Her appearance features fair skin and long, curly black hair meticulously parted down the middle, reflecting her fixation on symmetry. The kanji composing her first name "Chiri" (千里) hold meanings central to her character: they can combine to form the first character of "umeru" (埋める, "to bury"), aligning with her frequent use of a shovel as a weapon. These kanji also form part of "senrigan" (千里眼, "clairvoyance"), occasionally manifested through a third eye appearing on her forehead.

Violence defines her. Provoked by imperfection, she enters murderous rampages, employing knives, razors, or characteristically, a shovel. These episodes target classmates and teacher Nozomu Itoshiki, resulting in her status as a wanted fugitive. She possesses extensive knowledge of violent historical revolutions and purges, with ambitions of global conquest through insurrection. Her psychological background includes childhood hallucinations, paranoia, and disturbing delusions, contributing to social isolation. Harumi Fujiyoshi was her only childhood friend, reaching out during her lonely transfer student years, though their friendship remained complicated by mutual misunderstandings.

Her relationship with Nozomu Itoshiki intensified after accidentally sharing an infirmary cot, leading to persistent demands for marriage. This pursuit involves possessiveness and extreme retaliation against perceived romantic rivals, including attempts to eradicate humanity. Despite this fixation, she frequently clashes with his apathetic demeanor. Kafuka Fuura often manipulates or enables Chiri's violent tendencies.

Across the series, her behavior escalates in volatility. Early depictions focus on enforcing order through intimidation; later chapters reveal more explicitly murderous actions, including threats, stabbings, and killings. She becomes implicated in broader conflicts, like plots involving "ushi no toki mairi" curses. In the anime adaptation, a running gag visualizes her spoken punctuation marks. Her family includes an older sister, Tane Kitsu; she bears no resemblance to her parents, a source of irritation.

Her name derives from "kitchiri" (きっちり), meaning "precisely" or "exactly," reflecting her inflexible worldview and role as a symbol of rigid conformity's destructive potential.