Sumire commands the Rooster Squad within the all-female Akane Class ninja community as its serious and disciplined leader. She masters "tomeika," an invisibility ninjutsu, though perceptive ninja like Tsubaki can pierce its veil. Responsibility and diligence define her values, while irresponsibility sparks her disdain.

Her leadership is tested by the perceived sloppiness of teammates Azami and Tanpopo. This frustration drove her to lead them into the mountains for intensive mind-retraining. Seeking solutions, Sumire consulted Tsubaki and even experimented by adopting Azami and Tanpopo's carefree lifestyle and speech for a day. However, this immersion only deepened her disappointment in their attitudes, reinforcing her commitment to their discipline.

Despite her typically stern demeanor, the mountain training and lifestyle experiment occasionally surface in moments of uncharacteristic carelessness. She maintains a meticulous approach to duties, habitually writing schedules directly onto a board with charcoal. Physically, she possesses purple eyes, wears glasses, and often styles her hair in twin braided ponytails tied back; she is left-handed. Her ninja outfit comprises a black shirt beneath a violet dress featuring a white collar secured by a purple ribbon, completed by long black shinobi sandals.

Sumire operates within the Rooster Team, one of the twelve Akane Class teams corresponding to animals in the Chinese Zodiac. Her background stems from a secluded ninja village where she adhered to its strict rule forbidding interaction with men, presented as dangerous beings, a rule later abolished.