Haruka Kazemachi is a second-year student at Seiou Academy and a central member of the Light Music Club. Her birthday falls on July 3rd, making her 17 years old and a Cancer under the zodiac, with an O blood type. Standing 156 centimeters tall and weighing 46 kilograms, her physical measurements are listed as 80-56-83 centimeters. She has brown hair that falls to her shoulders and purple eyes.

Coming from a musical family, Haruka serves as the main vocalist and a key figure in the all-girl band named Neuron★Cream Soft. Her musical talents extend beyond singing, as she is also proficient in playing the guitar and various other instruments, demonstrating noteworthy versatility as an all-around musician. Additionally, she takes on the role of composer and songwriter for the band, writing their music and lyrics.

Haruka possesses a serious and earnest personality, characteristic of her Sweet-type classification. However, her dedication to her craft can lead to a tendency where she becomes so intensely focused on her music that she loses awareness of her surroundings. Beyond music, her hobbies include applying appliques to fabric or other items, writing songs, and appreciating music. Her favorite food is soft-served ice cream, while she notably dislikes squid.

In the context of the story, Haruka is primarily defined by her activities within the Light Music Club and her involvement with her band. Her key relationships are centered around her bandmates in Neuron★Cream Soft, though interactions with other students such as Fumio Murakami and Kuroko Shirai are also highlighted in various scenarios. Her development as a character is tied to her musical growth and her interactions with other girls at the academy. Her notable abilities include her vocal performance, instrumental skill on multiple instruments, and her capacity for musical composition and songwriting.