Tamaki Kousaka originates from the visual novel *To Heart 2* and features prominently in its adaptations and spin-offs. She possesses waist-length red hair, typically worn in a ponytail or half-updo, with spiky bangs and brown eyes. Her physical measurements are 165 cm in height with a bust-waist-hips ratio of 89-58-82 cm. Born into wealth, she is adept in traditional Japanese arts and customs while carrying herself with a modern demeanor. Childhood friends with Takaaki Kouno and Konomi Yuzuhara, she left them to attend an all-girls boarding school in a remote mountain area. She later fulfilled a promise to return during her final high school year, transferring into Takaaki's school. She is the older sister of Yuuji Kousaka. Her personality blends confidence, maturity, and a protective, maternal instinct towards her childhood friends. She often calls herself "Tama-onee-chan" (Tama Big Sister), reflecting her self-appointed guardian role. Despite her refined presence, she harbors a mischievous streak and reacts with violence when provoked—especially towards Yuuji, whom she disciplines physically through face-grabbing or iron-claw attacks. She values authenticity, criticizing kindness used as a shield to avoid causing pain. Her return in the original storyline disrupts Takaaki and Konomi's daily lives. She openly displays possessiveness over Takaaki, hinting at romantic interest beneath her sisterly facade. In the spin-off *Another Days*, her role shifts to supporting character. She monitors Takaaki's interactions with new heroines, warning him about the emotional fallout of his overly accommodating behavior—such as when he humors a primary school admirer, Nanako. Episodic OVAs like *adnext* showcase her frustration when Takaaki addresses her formally ("Tamaki-sama") instead of intimately. Her character design and narrative presence remain consistent across media, emphasizing her dual identity as a grounded authority figure and a vulnerable romantic interest.