Rizumu is a student that goes to the same school as Aira and also is in the same class. Rizumu is ambitious, her dream is to perform the "Aurora Rising" one day so that she can bring her mother back. She's good at dancing. She always tries to do her best and follows her dream. However her grades are shown to be very bad. She is the type of energetic girl who doesn't care about her schoolwork. It is stated that she may be the type of girl which love becomes power and fuel for her. She also seems to be quite knowledgeable about love from a certain book of hers. She also loves food. Her father mentions in episode 22 that one time she ate a lot of chocolates in one day. She especially loves meat. However because she is so determined to do the Aurora Rising, sometimes she tries to hard and becomes a bit selfish. She is shown to always be on fire after Hibiki flirts with her. She made Hibiki carry all of her candy on the Halloween episode and watched him mostly when Calling's was performing their new song. She remains optimistic and aims to be the best in dancing, singing and to be the Prism Queen by performing the Aurora Rising to bring back her mother. In the end of the second episode, she finally was able to complete her first Prism Jump, Heartful Splash. However she also came up,(or showed for the first time), with many of the other standing prism jumps such as: Stardust shower, Happy Macaroon Spin and Fun Fun Heart Dive etc., though they are frequently used by both Mion and Aira at times. She has currently told only Aira and Mion that her mother is the legendary prism queen Kanzaki Sonata and will do the Aurora Rising at all costs even sacrificing MARs.
Even before the series started, Rizumu was revealed to have been a student at Pretty Top. Aira and Rizumu meet the first time, in the mall, where they both run into each other(Rizumu has a graceful landing while Aira falls on her face). Later they perform together in their first Prism Show where Aira surprises her with her Prism Jump, Fresh Fruits Basket.
Aira helps Rizumu with her great fashion sense and picks out an outfit for her, which she wears while she performed her first Prism Jump. Rizumu wanted to know, how Aira was able to do the Prism Jump and even challenged her to a dance off which Callings watched in the beginning of the 2nd episode.
After some time the two become good friends, they both get a scholarship for the dance school, where she also meets Bear-Chi her coach. It is revealed later that her mother was the legendary Prism Queen Kanzaki Sonata. She is also shown to be closest to Hibiki from Callings. She blushes a alot around him. Hibiki seems to find Rhythm interesting. Just like Aira and Shou they both are shown to have created a relationship too in episode 18 of the anime. Rizumu is shown to have the same birthday as Aira. In episode 22 she gets a present from Hibiki, the person she likes the most in Callings, He gives her chocolates so Hibiki might be good at making chocolates or he is a good cook. Callings also sings for her and Aira before giving the presents. They are both embarrassed because the song they sang is a new song that they haven't published yet meaning they are the first to hear it. She is obviously in love with Hibiki noted throughout the current episodes. She had a rivalry with Hibiki's revealed sister, Toudou Kanon about Hibiki which he didn't know about. She continues to argue alot with Mion even though they have fun with each other as best friends along with Aira. Just like Mion, she gets into fights with Serena and Kanon.
Rizumu has brown eyes and orange hair. Her orange hair is tied on the right side in a small ponytail with a heart hair tie. She usually wears boyish clothes, she has a bad taste in fashion. It seems like she hasn't cared about fashion, before Aira made her an outfit. She like to wear parkas because they are easy to run, do a Prism Jump and dance in. However she does wear miniskirts and long stockings. It is stated by Aira's mother Omi Harune that she looks just like Sonata when she was younger.
During her first Prism Show, Rhythm tried her best but couldn't satisfy the crowd, because she couldn't do a Prism Jump. However she revealed that she was good at dancing.
In the second show, Rhythm wasn't allowed to wear her perform costume, instead she wore the outfit Aira chose for her. After some time, she heard her costume sing, and managed to perform a Prism Jump, called "Heartful Splash". She and her partner and best friend Harune Aira perform the Prism Show together. In the beginning she just wanted to do the Aurora Rising and was so stubborn but then she started to enjoy the Prism Show. She placed second in the Tiara Cup and is performing in the Summer Queen cup with Aira because they are best friends. She will probably continue the Prism Show because it is so fun. She is also debuting with Aira and Mion in a new unit called MARs and is confirmed to have succeeded in doing the Aurora Rising and Aurora Rising Final.