Yuka is a fair-skinned girl with long dark brown hair with braids on the side, and dark violet eyes. She has a well developed body that is covered with bruises due to the bullying of her ex-best friends.
Although she didn't get her stick, her emblem is shown to be the roman numeral "XIII".
Before Yuka started the middle school, she was a very cheerful and bright girl, but she soon became a suicidal, dark and gloomy girl after she has started to be attacked and harassed by her ex-best friends.
Yuka was the best friend of an unnamed girl with short black hair, but, soon the girl started to be jealous of Yuka's athletic talent, both girls liked a boy from their school, when the boy revealed he had a crush on Yuka, her ex-best friend became a bully and began to mistreat her and beat her mercilessly.
During her time of being harassed and bullied, she vented on an Twitter account named "Girl in the corner", talking about how she wanted to die and how she hoped the "urban legend" about the Magical Girl Site was true.
One day, she decided to finally commit suicide by getting hit by a train, but before she was, she became a magical girl. She posted on her Twitter account "It's coming" over and over again. Her Twitter account was deactivated right after she posted it.
Even though Yuka didn't get her stick from Ni, the ability of it allows her to trap all the oxygen from her surroundings in her stick, it is not specified if it has an area limitation. It is also shown that the user's oxygen is not affected, this was shown when Alice Misumi used it.
- The name Yuka means "hot water" (湯) (yu) and "flower" (華) (ka).
- Yuka's surname Sumikura means "housing" (住) (sumi) and "warehouse" (倉) (kura).
- Yuka is one of three magical girls to not get a stick.
- It is not known why Yuka never told her parents that she was being bullied.
- Yuka's ex-best friend looks a lot like Hyoka Nagatsuki.
- Yuka never had the chance to use her Stick, so it is implied that she was turned into sperm and absorbed by the Tempest.
- Yuka is in 8th grade.
- Yuka's hobbies include reading, studying, cooking and athletics.
- Yuka likes sweetswhile she dislikes spicy foods and reptiles.
- Yuka used to like track and field.
- Yuka's birthday is on June 19.
- Yuka's zodiac sign is Gemini.