Sumire Hirose is a third-year student at Shiraitodai High School in West Tokyo. She is a close friend of teammate Teru Miyanaga and the only person known to Teru who seems to have had prior knowledge of Saki's existence. Sumire is calm and polite to her friends and opponents. She never rushes to make her decision and always calmly thinks about it throughly.
Sumire's ability is called "Piercing arrow shots." It allows her to get a direct hit on a player of her choice by changing her hand to target a certain discard. It targets what would be the best offensive play, and can be dodged by making defensive or plain bad play. Unfortunately, the ability has a tell: when she's about to use it, Sumire's hand moves a bit and she looks at the player she is aiming at. However, the hand movement is so slight (only moving a few millimetres back) that her own team mates didn't know about it until Yuu Matsumi seemingly effortlessly dodged her piercing shots.
