Suruga has brown eyes and short, dark bluish hair. As a dedicated member of the basketball team, she possesses a toned, athletic build. Despite her physical strength and confidence in her abilities, she jokingly remarks that her bust size may not be enough to catch Koyomi Araragi’s attention.

Her fashion sense matches her energetic and boyish personality. Outside of her Naoetsu Private High School uniform, she typically wears sleeveless tops and shorts. A notable aspect of her attire is her consistent use of cycling shorts, which she refers to as her underwear. This candid revelation surprises Koyomi, as it implies she does not wear traditional undergarments.

Suruga identifies herself as a lesbian, a fujoshi, and a masochist. Her hobbies include reading yaoi literature, running, and playing basketball. While she is generally cheerful and candid, her personality carries certain contradictions. Tsubasa Hanekawa once described her as “polite but inconsiderate,” capturing the mix of social grace and emotional detachment she can exhibit. She is also known to be disorganized in her personal space, often relying on Koyomi Araragi to help clean her messy room.

When confronted by Rouka Numachi about rumors regarding her sexuality, Suruga openly confirms that she likes girls but adds that she also likes boys. Numachi points out Suruga’s tendency to observe her basketball teammates and opponents with unusually intense focus, suggesting a stronger attraction to women. While Suruga denies having such thoughts during games, she privately questions whether that denial is entirely true. Although she rarely shows romantic interest in men, she has displayed a teasing and flirtatious attitude toward Koyomi. Initially, this behavior was meant to distract him from Hitagi Senjougahara, but it later evolved into genuine camaraderie. In her conversation with Numachi, she remarks that she hasn’t thought much about her ideal type, but she imagines she’d prefer someone “on the small side and kind,” which given frequent references to Koyomi’s height may subtly refer to him.

Beneath her otherwise lively and open nature lies a darker tendency: intense jealousy that can manifest subconsciously. This suppressed envy ultimately played a key role in her transformation into the Rainy Devil, where her inner resentment and desire to harm others came to the surface under the influence of the oddity.

During her elementary school years, Suruga came into possession of what she believed was a monkey’s paw, though it was later revealed to be the Rainy Devil, an oddity capable of granting wishes at a steep cost. At the time, she was struggling with being teased for her slow performance in track and field. Hoping to overcome this, she wished to become the fastest among her classmates. Shortly afterward, her rivals in a race were mysteriously attacked and failed to show up the next day. Similar incidents continued, leaving Suruga frightened, especially after reading The Monkey’s Paw, a story with eerie parallels to her own situation.

Suruga eventually shifted her focus to basketball, where she quickly rose to prominence as the school’s ace player. Her talent caught the attention of Hitagi Senjougahara, then the star of the track team. The two became close friends, forming a duo Suruga fondly referred to as the “Valhalla Combo” (ヴァルハラコンビ Varuhara Konbi), combining “varu” from Kanbaru and “hara” from Senjougahara. During this period, Suruga largely forgot about the cursed monkey’s paw.

Upon entering high school, Suruga discovered Hitagi’s secret and, much like Koyomi Araragi, was confronted and physically threatened by her. Unlike Koyomi, however, Suruga heeded Hitagi’s warning and distanced herself. Later, after learning that Koyomi and Hitagi had begun dating, Suruga began to secretly follow him, driven by curiosity and unresolved feelings.

Hitagi Senjougahara
Suruga and Hitagi were once close friends, forming a duo she nicknamed the “Valhalla Combo” during their time as athletic stars in junior high. Suruga admired Hitagi greatly, and their bond was rooted in mutual respect and shared ideals. However, their friendship became strained after Suruga discovered Hitagi’s secret. Following a violent confrontation, Suruga distanced herself, respecting Hitagi’s demand for silence. Despite the rift, Suruga continued to harbor lingering feelings and admiration for her.

Koyomi Araragi
Initially, Suruga viewed Koyomi with suspicion after discovering he was dating Hitagi. This led her to secretly stalk him. Over time, however, the two developed a more comfortable and supportive relationship. Though she often teases and flirts with Koyomi, their bond evolves into a genuine friendship built on trust and mutual understanding. Koyomi also plays a key role in helping Suruga confront the Rainy Devil and reclaim control over her own life.

Rouka Numachi
A former rival and fellow basketball player, Numachi shares a complicated connection with Suruga. Their past is marked by both competition and unspoken emotions. In Hanamonogatari, Numachi serves as a catalyst for Suruga’s emotional and psychological growth, challenging her to confront her identity, desires, and fears. Their interactions reveal deeper truths about Suruga’s internal struggles and the lingering impact of unresolved jealousy and attachment.

Tooe Gaen
Suruga’s mother, revealed in later installments to be Tooe Gaen, links her to the powerful and mysterious Gaen family. Though her mother passed away when she was young, Tooe’s legacy and ideals continue to influence Suruga’s actions and beliefs, particularly in regard to helping others and facing the supernatural.