|Eye color||Brown / Black (Anime)|
|Height||138 cm (4'6")|
|Weight||34 kg (75 lbs)|
|Manga||18. Kagerou Daze I|
|Anime||04. Kagerou Daze|
|Novel||カゲロウデイズ III -the children reason-|
|“||I kind of hate summer.||”|
- Hiyori is a young girl with long black hair, which is tied as two ponytails laying on her shoulders and messy bangs. She has dark brown eyes. She is usually shown wearing a black T-shirt with a pink strapped dress and black shorts. On her feet she wears brown sandals with pink straps.
- In Mekakucity Actors she alternatively appears wearing a casual attire, consisting of a pink short-sleeved sweater and a white shirt with a grey polka dot pattern, combined with a yellow skirt. Her legs are covered by black socks that reach high onto her thighs. She also wears pink slippers.
- In Wannyanpu's fanmade PV, she is seen with short black hair and a white shirt with a black strapped dress on top. She also has a bracelet and wears black sandals.
- Hiyori is a young girl who admires the big city. She is incredibly active and stubborn, and was the person who dragged Hibiya to the city with her. She is popular among her classmates, but not interested in romantic things, and even Hibiya is only considered a "convenient classmate who listens to what she says."
- She seems to be a messy and careless girl, as she would leave trash all over her brother-in-law's house. She has a sharp tongue and does not hold back to show a mean and insulting attitude towards Hibiya, often ordering him to do various errands for her. Despite her pessimistic behavior she has a weak spot for cute and girly things. When being with people she admires however, such as Momo and Konoha, she tends to show a sweet and excited side of herself, which can turn out a bit too protective.
- Her favorite animals are cats.
- Her Japanese name origin means "weather".
- Because of the original Kagerou Days video not featuring Hiyori's design, Wannyanpu made her own personal design for her. However, this design was not official, creating confusion for the fans once she was featured in several songs without her fan-made design.
- She is a big fan of Momo Kisaragi.
- She has a huge crush on Konoha; likewise, Hibiya is in love with her.
- "My sister ran away from home. She probably didn't even know that I was born. The first time I saw her was when she was in a coffin." - Hiyori to Hibiya (-the children reason-)
- "Key-rings and stuff like that aren't my thing. Well, even if they were, I'd never buy a dinosaur one." - Hiyori to Hibiya (04. Kagerou Daze)
- "Don't be stupid! Somebody that cool couldn't possibly die! Unlike a pipsqueak like you!" - Hiyori to Hibiya when he suggests that Konoha could have died. (04. Kagerou Daze)