TV-Series
Description
Nadeko Sengoku is Tsukihi Araragi's childhood friend since elementary school. She developed a longstanding crush on Tsukihi's older brother, Koyomi Araragi after he fixed her bicycle during a visit to their house, and affectionately called him "Koyomi-onii-chan." Her feelings endured despite a six-year gap in contact where Koyomi seemed to forget their meeting. She grew up pampered by parents who superficially called her "cute," resulting in a sheltered upbringing and emotional stunting. This manifested in simplistic vocabulary, frequent misspellings, and using third-person self-reference (often with a lower-case "i" in English) to maintain a childlike demeanor, along with habitual name puns.

Physically, Nadeko is 153 cm tall and weighs approximately 38 kg, with dark brown hair (black in the original novels) and brown eyes. She initially wore concealing outfits like baggy denims, an orange newsboy cap, and layered jackets to hide scars from supernatural curses. Long forelocks covered her eyes and avoided direct gazes, providing security. Later, she switched to more comfortable clothing, including skirts, and eventually cut her hair short. Her personality centered on shyness and avoidance; she disliked physical contact, struggled socially, and maintained a victim complex to deflect responsibility. She harbored deep dependence on Koyomi for emotional support, using her unrequited feelings as a shield against other relationships and personal growth. This facade hid true frustrations and self-loathing, occasionally surfacing—like Koyomi noting her "serpent-like glare" when she briefly styled her bangs aside.

A pivotal moment occurred when she rejected classmate Sunshi Sajou, triggering the jagirinawa curse—an invisible snake coiling around her body, causing scalelike scars and threatening her life. This curse manifested after she performed incomplete snake-sacrifice rituals at North Shirahebi Shrine. Koyomi and Suruga Kanbaru intervened, breaking the curse in a dangerous confrontation that injured Koyomi. This intensified Nadeko's reliance on him. Her attempts to entice Koyomi grew overt, like inviting him to her home in a revealing outfit and playing suggestive games such as Twister, while discussing rumors of lingering curses at her school.

Her character changed drastically during "Nadeko Medusa." As class representative, she struggled to mediate conflicts stemming from Deishuu Kaiki's prior manipulations. After encounters with Ougi Oshino—who criticized her avoidance—and manifestations of white snakes, she confronted the serpent entity Kuchinawa, revealed as a projection of her self-criticism. Tsukihi cutting off her protective forelocks triggered a mental collapse. Deprived of shields, Nadeko lashed out at her teacher and classmates, exposing buried resentment and self-hatred. In this state, she ingested Kuchinawa's talisman, believing it would restore her hair and make Koyomi reciprocate. This transformed her into a vengeful snake goddess with white serpent hair and red eyes, wielding immense destructive power. As a deity, she resolved to kill Koyomi to eternalize her unrequited love, stating, "If I mean to have an unrequited love, it'd be a lot more romantic if he were dead."

Her godhood ended when Deishuu Kaiki, recognizing her deeper aspirations, dissuaded her by appealing to her secret passion for becoming a manga artist. He exposed her hidden sketches—created over years and stashed in a forbidden closet—as proof of untapped potential. Kaiki argued embracing humanity offered endless reinvention, unlike stagnant aberration existence. Nadeko relinquished her powers, abandoned dependence on Koyomi, and pursued art openly, marking significant growth towards a more honest, self-driven identity. In later arcs like "Koyomi Reverse," she appeared as an ex-god with a brash, tomboyish demeanor, drinking heavily and displaying rude mannerisms—traits she reportedly regretted, reflecting her ongoing struggle with self-reinvention.

Nadeko's relationships were instrumental. Her friendship with Tsukihi ("Rara-chan") provided childhood stability but catalyzed her breakdown when Tsukihi cut her bangs. Conflicts with Shinobu Oshino arose from Shinobu recognizing Nadeko's former dependent self avoiding growth. Ougi's manipulations targeted her victim mentality, underscoring themes of self-deception and transformation.