Hina Hikawa, the younger twin sister of Sayo Hikawa, is a cheerful and carefree first-year student in Keiho Women's University's Faculty of Human Sciences. She previously held the position of student council president at Haneoka Girls' High School. Blessed with exceptional natural talent, Hina masters new skills effortlessly, often requiring just one attempt. This innate ability allows her to achieve top academic test scores and instantly memorize complex sheet music, playing guitar with native-like fluency in English. However, this ease leads to quick boredom and difficulty understanding others' struggles with practice and effort.

Her personality is candid and often bluntly honest, sometimes inadvertently hurting feelings, particularly those of Pastel*Palettes vocalist Aya Maruyama, whose diligent efforts initially perplexed Hina. She frequently uses unique onomatopoeic expressions like "run" (translated as "boppin'♪") and "pipi" ("zappin'") to describe experiences. Over time, Hina developed genuine investment in the band, partly due to Aya's influence. She enjoys teasing friends and admits finding Aya's crying reactions "interesting."

Hina deeply admires her sister Sayo and started playing guitar after seeing her do so. She actively sought shared activities to bond, unaware this exacerbated Sayo's inferiority complex as Hina effortlessly excelled at everything Sayo practiced diligently. Their conflicting personalities caused frequent arguments, with Sayo initially resentful of their twinship while Hina embraced it. A turning point occurred when Hina confronted Sayo about quitting guitar, expressing raw emotion and apologizing for unintentionally causing pain. This led to greater mutual understanding and a warmer relationship; Sayo now treats her more kindly, and Hina openly expresses affection. Hina attends Roselia concerts to support Sayo, sometimes in disguise when asked not to.

As Haneoka's student council president, Hina generated creative but unconventional ideas, occasionally overwhelming vice president Tsugumi Hazawa. She spearheaded a successful joint school festival with Hanasakigawa Girls' School. Hina was the sole Astronomy Club member, jokingly called "The Weirdos Club" by peers, which deterred potential members. She collaborated with Hanasakigawa's Kokoro Tsurumaki on astronomy activities. After "The Mole Person☆Transport Mission!" event, Hina developed a fascination with extraterrestrial phenomena, cryptids, and the occult magazine "Supernatural Encounters."

Physically, Hina has sharp green eyes and light teal shoulder-length wavy hair with right-parted bangs, featuring tiny yellow-bowed braids on each side. Her casual style leans tomboyish with pants/shorts and a gingham jacket worn on or around her waist, contrasting with Pastel*Palettes' frilly performance outfits. She stands 156 cm tall. Hina enjoys volleyball, gum, candy, and junk food but dislikes bland foods like tofu skins. Her hobbies include making aromatic oils. Symbolically, her name "Hina" (日菜) incorporates "sun/daylight," contrasting Sayo's "night"-associated name.

Trivia notes include her struggles with map symbols despite high intelligence and identical height to characters Kasumi Toyama, Tsugumi Hazawa, Aya Maruyama, and Kanon Matsubara. In a Zombieland Saga collaboration, her design referenced Mizuno Ai with the title "Legendary Student Council President."