Chiri Kitsu is a student in Class 2-He, defined by her obsessive need for precision, order, and symmetry in every aspect of her life. This compulsion drives her to meticulously part her hair exactly down the middle and to demand strict conformity from others, often intervening forcefully to correct perceived irregularities. Her name derives from "kicchiri," meaning "precisely," reflecting this core trait.

She exhibits extreme and violent tendencies, especially when provoked or confronted with disorder. Her preferred weapon is a shovel, a choice linked to the kanji of her first name "Chiri" (千里), which can form part of the character for "umeru" (to bury). She frequently threatens or attacks classmates, particularly Nozomu Itoshiki, and has engaged in murderous rampages that made her a wanted fugitive. She possesses extensive knowledge of violent historical revolutions and purges, often referencing them, and practices occult rituals like the "ushi no toki mairi" curse. Supernatural elements include occasional displays of clairvoyance through a third eye, a pun on "senrigan" (clairvoyance), sharing two kanji with her name.

Her background reveals a troubled childhood marked by loneliness, hallucinations, and paranoia. As a frequent transfer student, she feared forming friendships due to anticipating future moves, leaving her isolated. Her only childhood friend was Harumi Fujiyoshi, though their relationship remained undefined due to missed opportunities for mutual acknowledgment. Chiri experienced delusions of frightening visions and imaginary enemies, contributing to social awkwardness and an unfulfilled need for affection, often making her a third wheel in social situations.

Her dynamics with Nozomu Itoshiki shifted dramatically after an accidental nap together in the same infirmary bed, leading her to persistently demand marriage despite revulsion toward his behavior. This pursuit involves intense possessiveness and extreme reactions to rejection or competition, including attempts to eliminate rivals or humanity itself. In the series' conclusion, it is revealed that Chiri and other classmates are manifestations of "Kafuka Fuura," a composite entity formed from girls who received tissue donations from a deceased girl named An Akagi. As part of this collective, Chiri marries Nozomu in a metaphysical resolution, though her individual memories of "Kafuka" fade.

Throughout the series, her character design includes visual gags, such as spoken punctuation marks appearing on-screen during her dialogue in later anime seasons. Her naturally curly hair—contrasting her straightened style—is occasionally referenced as another linguistic pun, as "chiri" can also mean "curly."