Sayako Hata is Asuka Ootori's civilian classmate and Nozomi Makino's close friend. A shy, bookish high school student in the Literature Club, she displays fierce loyalty, physically chastising Nozomi for inappropriate remarks about Asuka. Terrorist incidents deeply affect her; nearly being shot in an early attack influences Asuka to become a magical girl again. During a major Disas assault, Sayako overcomes her fear to protect the injured Nozomi, supporting her escape while drawing inspiration from Asuka's past heroism. Her sharp situational awareness leads her to warn Mia Cyrus of an impending attack, enabling Mia to counter it and winning Mia's gratitude.

Her storyline diverges between adaptations. The manga depicts her kidnapping by the Babel Brigade, forced transformation into the unstable illegal magical girl Sehkmet via the Ring of Ouroboros, disintegration into ash upon ring separation, and later resurrection through Asuka's latent magic. The anime omits this, showing her survival without transformation or death.

Interactions suggest possible romantic feelings. Sayako becomes flustered receiving Asuka's praise about her book passion, blushes while observing Asuka, and reacts physically to Nozomi's embraces, placing a hand on Nozomi's waist during one hug. Nozomi explicitly cites Sayako's "love of cool girls" as exciting. Sayako also recognizes the close bond between Asuka and Kurumi. Her interests include being a fan of *Revolutionary Girl Utena*.