"She was so kind and strong... She was the perfect older sister. "
- Persona 5 Royal: Supporting Character
Kasumi is a young girl with identical facial features to Sumire. However, her eyes are brown and more angular compared to her younger sister and she has auburn hair and a beauty mark next to her left eye. She also wears contact lenses and her gymnast outfit is pink instead of blue.
Because Kasumi was deceased right before the events of Persona 5 began, and thus was unable to speak for herself, most of her personality and history are only known by the accounts from Sumire's Confidant, as well as her behavior when she identifies herself as Kasumi.
Kasumi is largely implied to have the same personality as the "Kasumi" who is actually Sumire under Maruki's spell, aside that she is much more bold and confident and is fully consistent in her performances and cheerfulness, said to be consistently at top score during gymnastic competitions and would do her best to cheer up her sister or protect her from harm. She is also much more nimble, has better memory than Sumire and can execute complex gymnast moves without any issues, something that the fake Kasumi cannot do. Sumire had even described her as a "perfect sister." Despite this, Kasumi does have one inferiority compared to Sumire; she cannot cook as well as her.
While possessing obviously well-meaning intent on taking care of Sumire, Kasumi can be highly insensitive or oblivious to her younger sister's depression plummeting to near-suicidal levels because of her care. When Sumire's frustration and mental instability reaches its peak, Kasumi's response is to joke around her, resulting in her subsequent breakdown that led to Kasumi's death.
Kasumi is also said to not support handling matters for others to prevent them from being over-reliant on other people, something she doesn't follow towards Sumire.
Kasumi is an accomplished gymnast living alongside her sister Sumire Yoshizawa and the sisters' father Shinichi Yoshizawa, who was the host of a talk show at Akasaka Mitsuke. They also lived alongside their mother and grandmother. She and Sumire had been practicing gymnastics since childhood under Coach Hiraguchi who trained them with a spartan degree, although Kasumi had a much more natural and shorter learning curve compared to her younger sister. She also decides most of the matters between the Yoshizawa sisters, including designing Sumire's bedroom. This excludes preparing the dishes since she cannot do them properly.
Kasumi is said to be a literal gymnastic genius who constantly goes into local competitions virtually uncontested, and many people were stunned by her bold performances. She also promised Sumire that they would go to internationals as a duo one day, although this is a promise which can no longer be fulfilled.
Unfortunately, Kasumi doing most of the things for Sumire, in addition to Sumire not being skilled enough to go into gymnast competitions uncontested like Kasumi even if they received the same training, had resulted in Sumire developing a severe sense of inferiority towards Kasumi, and suicidal depression manifesting as a constant sense of worthlessness and (heavily implied) quick fatigue. She also had constant delusional thoughts about how she would either have to become Kasumi herself or die, despite being above average at the sport. This accumulated into Sumire running away from Kasumi and nearly throwing herself into traffic by accident when the sisters were heading back home after a training session, and she only survived because of Kasumi sacrificing herself to protect her. This occurred a month prior to the beginning of the sisters entering their first year of high school.
Shinichi mourned Kasumi with grief right after her death, and Sumire's mental condition worsened because she thought she was responsible for her death and stealing her dream, to the point that her survivor's guilt worsened her depression, even crippling her interest towards her daily routines. Sumire was pushed by Shinichi to meet Takuto Maruki for therapy on March 25th to prevent her from actually committing suicide. When Maruki was counseling with Sumire, she managed to make him activate his Persona's actualization. Maruki (subconsciously) made her believe that she is her sister Kasumi, and Sumire died instead, as that's what the former Sumire wanted. Since Maruki only made her think she's Kasumi, other people still see this "Kasumi" as Sumire, making them believe that she is delusional. However, she wouldn't be able to hear the truth directly from them, as she would instead hear "Kasumi" if people used her real given name.
Despite her death and Sumire's feelings of inferiority towards her, Sumire does genuinely respect and admire her as a person and the sisters did have a genuinely great relationship with each other. Kasumi also saw Sumire as a rival on near-equal terms instead of somebody to be looked down upon.
- "We're on. / Together. / With grace." (Showtime finisher)
- Sumire used to bring Kasumi to the shrine in order to pray for good luck prior to her major tourneys.
- Kasumi used to fear heights when she was younger.
- Kasumi's father Shinichi used to take her to the batting cages when she was a child.
- Kasumi enjoyed going to aquariums.
- Kasumi introduced Sumire to the gym seen in her Rank 7 Confidant.
- Kasumi's death is referenced during the animated opening of Royal, where Sumire dances while holding an umbrella on a rainy road. The real Kasumi died on a road during a rainy day while holding an umbrella.
- Kasumi died on March of 20XX, a month prior to the beginning of the protagonist's journey. This is implied by Sojiro Sakura on April 10th, who mentions a fifteen year old girl dying in a car accident.
- Kasumi has a beauty mark on the corner of her left eye. According to Chinese mole readings, people with a beauty mark on the outer corner of their eyes are generous, honest and peaceful, although they might also meet sudden death.
- There are unused models of Kasumi with her hair down.