Tsubasa Hanekawa is a high school classmate and close friend of Koyomi Araragi, serving as class representative at Naoetsu Private High School. Academically exceptional and consistently achieving top grades, she humbly downplays her knowledge with the phrase "I don’t know everything, I just know what I know," a statement notably reserved for Araragi as it pleases him. Her appearance features black hair, purple eyes, and glasses early in the series, often styled in braids with a cat-design hair ribbon. After the events of *Tsubasa Cat*, she cuts her hair short and switches to contact lenses. Following *Tsubasa Tiger*, her hair develops permanent silvery-white tiger-like stripes, which she dyes black daily.

Her family background involves significant instability and neglect. Her biological mother, who became pregnant at 17, committed suicide shortly after her birth. She was subsequently raised by a series of step-parents, none biologically related to her. In her current household, she lacks a personal room, sleeping in a hallway, and maintains distant ties with her guardians, who largely ignore her existence. Her stepfather struck her face, resulting in a visible injury.

Hanekawa presents a meticulously constructed persona of kindness, approachability, and emotional control, earning admiration from peers and teachers. Beneath this facade lies profound emotional suppression. She operates primarily through logic and social convention rather than genuine sentiment, internalizing trauma and negative emotions to maintain an image of flawlessness. This repression manifests supernaturally: during Golden Week, her pent-up stress merges with the oddity *Sawarineko* (Meddlecat), creating "Black Hanekawa"—an alternate personality that attacks others to drain their energy. Later, envy toward her step-parents' attempts at reconciliation without her catalyzes another aberration, "Kako" (Hysteria Tiger), which seeks to destroy homes.

Her relationship with Araragi begins when she deliberately initiates contact after a skirt-lifting incident, inserting herself into his life to provide support during his vampirism ordeal in *Kizumonogatari*. She sustains life-threatening injuries aiding him, leading him to heal her with his vampire blood—an act leaving traces of Kissshot Acerola-Orion Heartunderblade's power dormant within her. She develops romantic feelings for him, but her emotional suppression prevents her from pursuing them. After witnessing his relationship with Hitagi Senjougahara, her unresolved stress peaks, culminating in the Hysteria Tiger incident.

Her character arc culminates in *Tsubasa Tiger*, where she confronts and accepts her suppressed emotions, including envy and anger. She confesses to Araragi, is rejected, and acknowledges her pain, symbolizing her rejection of forced perfection. She declares her desire to be "impure" rather than "flawless," embracing human complexity. Post-graduation, she adopts a nomadic lifestyle, traveling globally for humanitarian work with NGOs. Her efforts in conflict zones earn her the epithet "Japanese Joan of Arc." She later transitions to war mediation, erasing national borders to end conflicts—a controversial approach resulting in her becoming internationally wanted.

In the spin-off *Magia Record*, an alternate depiction shows her as a magical girl whose wish—"I want to forget everything"—reflects her trauma. Her magical abilities involve memory-erasing flames, and her Doppel embodies the Sawarineko and Hysteria Tiger, representing her bifurcated negative emotions.

She possesses a natural ability to create aberrations from suppressed emotions, though this ceases after her self-acceptance. The lingering vampire blood in her system occasionally surfaces, as seen when reacting to Dramaturgy's briar thorn, temporarily granting her vampiric traits.