TV-Series
Description
Tsukiko Yahisa anchors all media as the central protagonist. She features long light brown hair styled short in front and long at the back, paired with light maroon eyes. Games and CGs typically obscure her eyes to preserve player anonymity, though later releases include display options.

Her core personality blends kindness, clumsiness, naivety, emotional sensitivity, honesty, and an intense work ethic. This drive often pushes her to physical collapse from overexertion. While her fundamental nature stays constant, personality nuances shift with player choices in games.

As the inaugural female student at the formerly all-male Seigetsu Academy, she attracts significant attention. A second-year Astronomy major, she actively participates in the Archery Club, Student Council, and clinic duties. She grew up with parents and a grandmother, though these relatives remain referenced rather than depicted.

Key relationships shape her history. She shares deep childhood bonds with Suzuya Tohzuki and Kanata Nanami, initially viewing them as brothers despite their romantic feelings. A separate childhood encounter with Yoh Tomoe involved gifting him a telescope and dubbing him "Hitsuji," with shared visits to her grandmother's house. She also experienced a forgotten childhood friendship with Kazuki Shiranui, severed by trauma that led him to withdraw for her protection.

Across narratives, she interacts with twelve zodiac-aligned love interests. "After Season" expansions introduce additional romantic paths through new characters and minor routes. Relationship dynamics vary by player choice, especially concerning childhood friends Suzuya and Kanata, where her feelings may or may not turn romantic.

Her journey balances complex relationships with academic and club duties. Plot points include confronting Kazuki Shiranui about their fractured past and managing Kanata Nanami’s severe heart condition—marked by fainting spells and hospital avoidance. Suzuya Tohzuki’s intensely protective, occasionally jealous behavior further impacts her experiences, notably when he aggressively intervenes against her admirers.