Kyoko Takimoto is Sakura Yamauchi's closest friend, defined by a protective and occasionally aggressive nature. She possesses a slim build, short brown hair reaching her neck, uneven bangs covering part of her forehead, thin eyes with reddish-brown pupils, and a small mole under her left eye. Her hair grows longer, extending just below her chin, following Sakura's death.

Deeply suspicious and hostile towards Haruki Shiga, whom she perceives as a threat to Sakura, Kyoko confronts him on a balcony about his trip with Sakura, knocks his book away, and explicitly threatens to kill him if Sakura is harmed. Despite this harsh exterior, she cares deeply for Sakura, attempting to dissuade her from associating with Haruki and visiting her in the hospital.

Her central relationship with Sakura is marked by mutual care and protectiveness; Kyoko's devastation at Sakura's funeral underscores their bond. After Sakura's death, Haruki invites Kyoko to a café where she reads Sakura's concealed diary, revealing Sakura's terminal illness, and breaks down. This moment shifts her dynamic with Haruki. When he asks to be her friend, she eventually accepts. One year later, they visit Sakura's grave together and proceed to Sakura's family home, indicating a reconciled friendship.

Kyoko's interactions with Issei Miyata begin antagonistically; she frequently scolds or physically chastises him for laziness, such as hitting him for neglecting classroom duties. Their relationship evolves into a romantic one. An after-credits scene implies their connection, confirmed in the sequel novel *To My Father and to Someone in My Memories*, where they marry and have a daughter named Anzu.

Kyoko's name incorporates the kanji meanings: "waterfall" (滝), "origin" (本), "respect" (恭), and "child" (子).