Toki Onjouji is a third-year student at Senriyama Girls' High School in North Osaka and a supporting character in the spin-off manga Saki: Achiga-hen episode of side-A. She was named one of Senriyama's ace players for the 71st Inter High School Mahjong Tournament despite being a relatively unknown player prior to it. Toki is physically weak, she is constantly being cared for by Ryuuka. Though she cares for Ryuuka and other members, she doesn't want to become a burden to them as she is always being hospitalized.