Sumire's father, Tanuki Shigaraki trained her from a young age, in order to avenge Danzo Shimura. Eventually, he bestowed her with Gozu Tenno. After the death of her parents, Sumire became an orphan and created the identity of "Sumire Kakei", deciding that it was best to wait and create a cover story before exacting her father's plan. Sumire eventually became the representative of her Academy class.
Sumire is a fair-skinned young girl with purple-coloured eyes and hair, the back of which is tied into two long braided ponytails. Her hair frames her face and her bangs hang just above her eyes. At some point, her father placed the formula for the Gozu Tenno on her back.
When under the identity of Sumire Kakei, she donned a long-sleeved black shirt beneath a violet dress that has a white collar on it, knotted by a purple ribbon, resembling a seifuku overall with black stockings. While undercover, Sumire wears a cracked pale-white mask with two horn-like disfigurements and a white cloak. After her identity is discovered, Sumire wears a purple qipao top with fuchsia-coloured trimmings tied by a white obi and baggy pants. Additionally, she wears long black gloves with bandages tied around her wrists and calves.
Having gone through arduous training since a young age, Sumire is a very stealthy and capable kunoichi. Thanks to her link with the Gozu Tenno, she is able to summon Nue to assist her, and has shown the ability to create a snake-like mass of dark chakra. She has also shown considerable skill in melee-combat, being able to fight on par with Mitsuki for a while. Her most powerful asset, however, is her deceptive and manipulative nature that has allowed her to forge herself a new identity, that of a meek and ordinary young girl. At the same time, she is very stealthy in general, able to effectively conceal her presence, making it very difficult to locate her.
- "Sumire" means violet.