Sayaka is a girl of average height. She has long dark violet hair with bangs that is styled into a ponytail tied with white ribbon, empty dark violet eyes and light pink lipstick. 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.
Sayaka is an intelligent and serious girl, who deeply cares about the school and Student Council. She is also endlessly loyal to the Student Council President and Sayaka is willing to do anything for her. It seems that she has a crush on Kirari as Sayaka 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.
Kakegurui - Compulsive Gambler
During the events of the first Season, Sayaka was explaining and managing the debt-swap game. She then observed the game between Yumeko, Mary, Nanami and Jun, specifically because the president wanted to learn more about Yumeko. Sayaka was impressed by them playing. When Jun wanted to attack Yumeko, she tazered him. After Kirari left for a family meeting, she was distraught. She was shocked to learn, that Kirari slipped in as the vice president. She also watched the Tarot card game, hoping for Kirari to win, relieved it ended in a tie.
Sayaka didnt take a liking to the presidential election, especially with the Momobami Clan being present too. She feared, that Kirari would lose her position and had to leave the school. She tries to call out Kirari, but couldnt change her mind. During the gambles, she stands next to her, threatening others that get to close, like Horo, with a tazer.