Toyama Kasumi is the main protagonist of the BanG Dream! franchise. She is a second-year student at Hanasakigawa Girls' High School and the leader, vocalist, rhythm guitarist, and songwriter for Poppin'Party.
Kasumi lives with her parents and has a younger sister, Asuka - whom she calls "Aa-chan" - however, it's not always clear who is the more responsible out of the two.
When she was looking at the stars one night as a child, she heard a sparkling "Star Beat", and ever since that, she's been searching for it. She believes that she found it after she saw her guitar for the first time, and when she formed Poppin'Party.
Kasumi has purple eyes and brown hair worn loose with segments pulled up into star-shaped buns. Her short bangs are framed by longer forelocks held by red star-shaped clips.
In her initial casual wear, she wears a long, baby blue button-up t-shirt dress accompanied by a yellow flannel tied along her waist. She also pairs it with a silver star necklace and a black watch.
During winter, she wears a red collared shirt, a yellow sweater which has white stars on it, a black miniskirt and a pair of tights. During summer, she wears a polka dot white T-shirt with transparent sleeves and a blue skirtall. The outfit is completed with a necklace that has three stars on it.
Cheerful and high-spirited, Kasumi is a playful, active, and generally positive girl that always finds something to be excited or passionate about. She easily makes friends and gets along with everyone, regardless of their personality.
She, alongside with Tomoe, are capable of sharing a mental wavelength with Kokoro. She is also the type to believe in (or fall for) the strangest explanations. However, Kasumi is also quite forgetful, tending to do important things by last moment (though unintentionally so.)
She loves to tease Arisa, but given her kind personality, it's hard to tell if she is deliberately trying to provoke her or if she's oblivious. At times she can also behave melodramatically.
A list of characters Kasumi interacts with in the game (during Lives and in the dialogues at the end of every game).
Toyama (戸山) can be split into two parts: To (戸) which means "door" or "entrance" and Yama (山) which means "mountain". Toyama also refers to the Shinjuku ward.
Kasumi (香澄) can be split into two parts: Ka (香) which means "a pleasant smell" and Sumi (澄) which means "clear" or "pure".
- Her personality and character were the complete opposite in the original storyline - she was depressed, lonely, reserved, and had barely any presence and very low self-esteem due to being bullied when she was younger. As a result, she started hating singing, thought of herself as below average compared to everyone else, and regarding her hobbies (collecting star-shaped things) as childish as well. She wore glasses all throughout her life before switching to contact lenses in high school as an attempt to change herself.
- Kasumi also had two older sisters.
- She is not a good swimmer unlike her sister, who was a member of Hanasakigawa's swimming club.
- ESP Guitars has released a real-life version of Kasumi's guitar, Random Star, alongside Tae's guitar, Rimi's bass, and other BanG Dream! merchandise.
- Although Kasumi's hairstyle is often mistaken for cat ears, it is actually her own attempt to make her hair in the shape of a star. Even when it rains, her hairstyle is never affected.
- In the Taiwanese and Chinese fandom, however, Kasumi's hairstyle is commonly described as 'sticky rice dumplings' instead, which is the festival food of the Dragon Boat Festival.
- She was one of the few girls unable to tell that Wanibe Nanana and the keyboardist of Glitter*Green were the same person until witnessing her remove her glasses.
- She's childhood friends with Hagumi, but Hagumi only realized it when Kasumi didn't have her cat ears (as she used to wear twin tails when she was younger).
- She has the same height as Tsugumi, Aya, Hina, and Kanon.
- Kasumi has a special ability to detect if Saaya's bakery made a new bread type by sniffing her.
- She dislikes all kinds of horror.
- In My Design, My Texture, Kasumi reveals that she has started growing herbs together with her sister.
- She appeared in the 1st episode of Future Card Shin Buddyfight.
- Her name, Kasumi, pays homage to Kazumi Tokiwa, one of the members of Milky Holmes Feathers which was also portrayed by Aimi. The other member being Alice Myojingawa, portrayed by Itou Ayasa.
- Kasumi losing her voice in the 10th episode of BanG Dream! 1st Season is a callback to Aimi losing her voice during BanG Dream! 1st Live: I started a band in spring!.
- In the A Certain Scientific Railgun T collaboration, her character design was based on Misaka Mikoto.
- In Senki Zesshou Symphogear XD Unlimited's collaboration with BanG Dream! Girls Band Party!, her 2nd stage outfit was used as the design for Tachibana Hibiki's card.
- BanG Dream! Manga - Volume 1
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- Band Girls of the Dead/Event Story