**Background and Creation** Created fifteen years before the main events by the Occult Research Club, Yotsugi Ononoki emerged when members resurrected a neglected human corpse into a doll-like tsukumogami shikigami. She selected Yozuru Kagenui as her master, rejecting Tadatsuru Teori and inadvertently igniting their rivalry. Each club participant suffered a curse: Izuko Gaen in the head, Kagenui and Tadatsuru in the legs (barring ground contact), and Deishuu Kaiki with Meme Oshino in their torsos. Yotsugi retains zero memories of her human existence before resurrection. **Appearance and Mannerisms** Yotsugi resembles a 12-year-old girl with turquoise hair, green eyes, and pointed ears, crowned by an orange hat featuring googly eyes. Her standard attire includes a frilly orange dress, blue-and-grey striped stockings, and yellow boots. After facing God Nadeko in *Nademonogatari*, she briefly sported shorter hair with a yellow beanie, green jacket, white shirt, and red pants before reverting to her original look. While impersonating Tsukihi Araragi’s doll, she often dons a kimono. Her speech remains consistently flat and monotone, initially ending phrases with "Boku wa kimegao de sou itta" ("I said, with a posed look") while using the masculine pronoun "boku." She later discarded this phrase out of embarrassment and discourages its mention. She frequently addresses others with sibling honorifics, calling Koyomi Araragi "oni no onii-chan" ("devilish big brother") and Kagenui exclusively "Onee-chan," while adopting the catchphrase "yay, peace peace" alongside a peace sign. **Personality and Relationships** Beneath her expressionless exterior, Yotsugi harbors genuine emotions. She considers Koyomi a friend, advising him from that stance and resisting harming him despite obligations. She resents Shinobu Oshino, mocking her age, and cultivates contempt for Tsukihi Araragi while living with the family. Conversely, she bonds strongly with Nadeko Sengoku, supporting her and assigning nicknames. Her identity exploration involves adopting phrases and gestures influenced by others, reflecting her malleable nature as a human-convenience "doll." She also exhibits an appreciation for muscles. **Abilities** Yotsugi wields "Unlimited Rulebook," a versatile power enabling projectile finger-fire, limb detachment, and telekinetic propulsion. A notable application is "Unlimited Rulebook: The Disengagement Edition" for rapid escapes. Her immortal oddity resilience allows regeneration from catastrophic damage. **Key Plot Involvement** In *Tsukihi Phoenix*, Yotsugi and Kagenui attempt to kill Tsukihi Araragi for being an immortal oddity; Yotsugi obliterates Tsukihi’s upper body, provoking Koyomi’s rage, then loses an off-screen battle to Shinobu. During *Mayoi Jiangshi*, she questions Koyomi about spirits like Mayoi Hachikuji’s happiness and purpose. In *Shinobu Time*, she rescues Koyomi and Mayoi from the Darkness, distracts Koyomi with a kiss to awaken Shinobu, and guides them to Izuko Gaen while avoiding direct involvement. For *Hitagi End*, she delivers Gaen’s warnings and bribes to Deishuu Kaiki, cautioning against uncharacteristic actions. In *Zoku Owarimonogatari*, a mirror-world manifestation of regrets exaggerates her expressiveness—smirking and grinning—contrasting her usual stoicism; she self-lobotomizes to revert upon sensing Koyomi’s discomfort, underscoring her internal conflict between emotions and her doll role. **Character Development** Yotsugi evolves from a detached shikigami into a complex individual forming genuine attachments. She becomes Koyomi’s protector, resides with the Araragi family, and partners frequently with Nadeko Sengoku. Her narrative role expands as narrator of *Orokamonogatari* and protagonist of multiple titular stories (*Yotsugi Doll*, *Yotsugi Buddy*, *Yotsugi Shadow*, *Yotsugi Future*, *Yotsugi Stress*). Throughout these arcs, her struggle to reconcile emotional capacity with her perceived emotionless oddity role remains central, particularly in explorations of regret and identity.