TV-Series
Description
Itsuki Harune, Aira Harune's younger brother, lives with his family in Yokohama, Japan. He has three sisters: eldest Aira, followed by him, and younger twin sisters Eru and Uru. Among the siblings, he exhibits a notably sensible and mature demeanor, often contrasting with Aira's clumsiness. He frequently engages in playful teasing directed at Aira, particularly regarding her interactions with Shou, yet remains fundamentally supportive of her pursuits. His responsibilities include looking after the twin sisters while Aira is occupied with work or Prism Star activities, and he assists in keeping Aira's involvement in Prism Shows a secret from their father.

During the Aurora Dream period at age 11, he occupies a secondary narrative role. He cultivates an early passion for enka music and demonstrates perceptive tendencies, especially concerning interpersonal dynamics involving Aira. His down-to-earth nature and occasional sarcastic remarks establish his foundational personality.

A significant evolution occurs three years later in Dear My Future when he is 14. Physically maturing into a handsome middle-schooler, he attracts attention, notably from Reina Miyama and initially Jae-eun. His life takes an unexpected turn when Mia Ageha orchestrates his surprise participation in a "Surprise"-themed Prism Show. Despite his primary focus on academic studies aimed at becoming a sports doctor—a consistent career ambition—he experiences unexpected enjoyment and exhilaration during this debut. His natural athleticism, acknowledged as proficiency in various sports, facilitates a smooth transition into Prism Show mechanics.

His trajectory shifts further when Yong Hwa observes his Prism Show potential and recruits him. Initially reluctant, he eventually co-founds the male Prism Star unit Love∞Mix. Balancing this new path with his medical aspirations, he discovers genuine appreciation for performing while reaffirming his dedication to sports medicine. This period reveals a development in his relational awareness; previously sharp regarding Aira's relationships, he initially appears unaware of Reina's affections. However, by Episode 51, he displays reciprocal interest by inviting Reina to spend time together.

Ultimately, he achieves his professional goal, becoming a sports doctor within the series' continuity.