Sasara Kusugawa begins as student council vice-president before ascending to president at Kaiyou High School, positioned one academic year above protagonist Takaaki Kouno. Her initial reserved and strict demeanor contributes to profound social isolation, leaving Marianne—affectionately called Ma-ryan or Maryan—as her sole friend. The prospect of Marianne's graduation deeply unsettles Sasara, driving her to dissuade Marianne from leaving—an act revealing her intense fear of loneliness and difficulty forming emotional bonds.

Sasara's interactions with Takaaki commence when he volunteers for a student council event. After she becomes president, specific circumstances appoint him as treasurer. Their collaborative work within the council catalyzes Sasara's gradual evolution from a cold, antisocial individual toward openness and emotional availability. Through this partnership, she forges a meaningful connection with Takaaki, culminating in romantic feelings.

Physically, Sasara stands 163 cm tall with blonde wavy hair featuring a middle part and spiky bangs, typically tied back and secured by a black ribbon headband. Her blue eyes accompany measurements of 87 cm (bust), 57 cm (waist), and 83 cm (hips). She predominantly wears the standard sailor school uniform, accessorized with a ribbon tie and thigh-high stockings.

Beyond the core series, Sasara appears in supplementary media: as a playable fighter-class character in the spin-off RPG *To Heart 2: Dungeon Travelers* and as a downloadable crossover combat unit in *Utawarerumono: Mask of Deception*. These portrayals remain non-canonical to her primary narrative and development.