Yuki has long light colored hair that extends past her shoulders and thin eyebrows.
When Yuki met Geto, Yuki wore dark colored long sleeve jacket over a sleeveless dark colored shirt, light colored pants, and light colored heeled shoes.
When Yuki met Aoi, Yuki wore riding goggles, a leather jacket, and dark colored pants.
Yuki has a relaxed and cheerful attitude. Among her peers she has reputation as a lazy sorcerer who never take on any missions and just travels the world. The reality she discreet with the approaches Jujutsu High takes. Her beliefs and research focuses on finding a way to wipe out Curses all together instead of exorcising them when they appear. Yuki remains calm when confronted by horrific ideas such as mass murder, choosing to assess the viability rather than the ethics behind them.
Years ago, she appeared to the elementary school student, Aoi Todo. Asking him what type of women he was into, she introduced the boy into the world of Jujutsu Sorcery.
On August 2007, Yuki meets with Geto, and talk about how they can stop cursed spirits from being created; which Yuki tells him that she has managed to figure out two ways for that to happen. Geto realizes a third possibility: the extermination of non-sorcerers. Yuki discuss is the idea with him and asks about his conflicting feelings towards normal humans. She tells him that he will soon come to his conclusion After talking, the two part ways. Yuki leaves reassuring Geto that Tengen has stabilized.
While her current abilities are unknown, her designation as a Special Grade Sorcerer designates her as having the ability to exorcise special level cursed spirits. She was also the mentor of Aoi Todo, a powerful 1st grade Shaman.
She possesses the Simple Domain technique as she was able to pass it on to her student, Aoi Todo.
She was able to save the others from Uraumes's Ice Fall technique by blocking it with ease.
- Yuki's surname contains the kanji for "ninety-nine" (九十九 tsukumo?), and her first name contains "reason, cause" (由 yu?) and "basis, foundation" (基 ki?).
- Yuki has a habit of asking men who she meets what type of girls they like, something her student Todo also does.