Shizuno Takakamo is a first-year high school student at Achiga Girls' Academy in Nara Prefecture and the main protagonist of the spin-off manga, "Saki Achiga-hen episode of side-A". In her elementary school days, she befriended Nodoka Haramura and together they played mahjong in Achiga's mahjong club. She was the club's second best player before it was disbanded. Upon seeing Nodoka on television as the middle school individual champion, she decides to re-establish the club upon entering high school. Her goal is to go to the national high school team tournament and play against Nodoka.

Shizuno is an energetic, athletic girl, and is easily excited. She enjoys hanging out with her friends whenever possible and tries to have as much fun as she can. She becomes a worthy opponent due to her never-give-up attitude. When the team falls into despair or lacks motivation, she will always step up and cheer them on.