Nadeko Sengoku is a junior high student initially characterized by shyness and reserve. Her physical traits include brown eyes, shoulder-length brown hair often veiling her face with long bangs, a height of 153 cm, and a weight of 38 kg. Early attire featured baggy, concealing clothing—an orange newsboy cap, pink blouse, orange jacket, and denim jeans—to hide scars from supernatural curses. Later, she adopted skirts and cut her hair short, discarding her signature bangs. Her personality displays childlike mannerisms: third-person self-references, simplistic vocabulary with frequent misspellings, and avoidance of eye contact or physical touch. Intensely self-conscious, she perceives constant observation by others, fostering a victim complex that deflects blame. She fixates dependently on Koyomi Araragi, addressed as "Koyomi-onii-chan," leveraging perceived innocence to evade confronting flaws or desires. Fragility masks manipulative tendencies and deep-seated resentment toward disruptions to her self-image. Raised sheltered by doting parents who reinforced her "cute" persona, she befriended Tsukihi Araragi in childhood and developed a crush on Tsukihi’s brother, Koyomi, after he repaired her bicycle. Years of minimal contact followed until middle school, where rejecting a classmate’s confession led to dual curses—*jagirinawa* (snake-cutting ropes)—from the rejected boy and a jealous peer. Invisible snakes coiled around her body when the curses activated at the aberration-tainted North Shirahebi Shrine due to an incomplete dispelling ritual. Her development spans multiple arcs. In *Nadeko Snake*, Koyomi and Suruga Kanbaru exorcise the curses while she remains passive. During *Karen Bee* and *Nadeko Pool*, she tests Koyomi’s attraction via provocative clothing, hinting at latent assertiveness. *Nadeko Medusa* triggers her psychological breaking point: pressured as class representative to resolve peer conflicts and confronted by Ougi Oshino over evading accountability, she hallucinates the serpent deity Kuchinawa—a manifestation of her self-loathing. After Tsukihi Araragi cuts her protective bangs, she snaps, publicly berating classmates and a teacher. In a fugue state, she consumes a talisman holding Kuchinawa’s remnants, transforming into a snake goddess with white serpent hair and crimson eyes. As a deity, she wields destructive power and vows to kill Koyomi to preserve her unrequited love fantasy. Her resolution occurs when con artist Deishuu Kaiki deduces her hidden aspiration to become a manga artist—a dream concealed in her closet, symbolizing fear of vulnerability. Kaiki convinces her that humanity offers limitless potential over godhood’s emptiness. Nadeko relinquishes her powers, abandons her fixation on Koyomi, and pursues manga professionally, later serializing three works. Post-transformation, she adopts a blunt, tomboyish demeanor, drinks alcohol heavily, and expresses regret for her former persona, signifying acceptance of a multifaceted identity beyond societal or self-imposed archetypes.