Sayaka is a girl of average height. She has long dark violet hair with bangs, styled into a ponytail tied with white ribbon. She also has empty dark violet eyes. She wears the Hyakkaou Private Academy issued uniform: a red blazer with black trim lining the cuffs and collar, a white button up dress shirt, a dark pleated skirt which is slightly longer than those worn by other female students, a tie, and black socks, as well as the academy's issued footwear, brown loafers with black soles. She wears light pink lipstick.
Sayaka is an intelligent and serious girl, who deeply cares about the school and Student Council. She is endlessly loyal to the Student Council President, Kirari Momobami and is willing to do anything for her. It seems that she has a crush on Kirari, as she expressed concern and sadness when the latter left without disclosing where she was going or why. While she seems to be a reserved and calm, her subduing of a violent student, Jun Kiwatari, and telling him what he now owes in the debt recollection game shows that she's every bit as terrifying as the rest of the Student Council. She's also somewhat jealous of Yumeko Jabami for capturing Kirari's interest and views her as a plague.