Chiasa has blood red eyes with an upside-down broken heart in her left eye. Her hair is straight, of medium length, and white in color, save for a blonde streak in her bangs (this is said to be the result of hair dye, as her natural hair color is black). She also has pale skin and freckles.
In her first appearance, she wears a white tanktop, a gray short skirt, and red 'tennant shoes."
According to Kimmy's investigations, Chiasa committed a series of crimes in the span of the last ten years. Her crimes include the arson of the Thompson's house, the murder of Azusa's parents, the murder of Homura Tomuson and the murder of the recently deceased Anzu Sayaka. Her whereabouts were unknown past a few comments from her boyfriend Masahiko Kurusu.
Azusa's dream sequence in Chapter 25 involves a girl with blood red eyes, who is most likely Chiasa.
She was unseen until she made her first appearance after Azusa's second swim meet, wherein she shoves Azusa to the ground and begins threatening her with a knife. Masahiko interrupts this encounter and fends Chiasa off so Azusa can run, getting himself badly hurt while Azusa calls the police. By the time the police arrive, however, Chiasa and Masahiko are both gone.
According to Masahiko, they are a couple and have been dating for some while. With the events of Chapter 34, however, their relationship status is currently unknown.
The Yakuza Edit
Chiasa is part of the yakuza and thought to be in the a quite powerful position, which is supported by the fact she's dating a high-ranking yakuza member.
Azusa is her cousin and apparently is hated on by her for no given reason.
It's unkown if and what she had against Akira, and if the fire she caused at Akira's house had any particular meaning.
Makoto is Chiasa's cousin, but unlike her position towards Azusa she doesn't seem to have an ill will against him and leaves him be. Whether she knows about his Yandere tendencies is unknown.
- Originally, she was supposed to be named Chiaki.
- Some theorize that she disguises herself as Chiriko Kasane, but this has yet to be seen.