A girl with a striking impression, featuring silky black hair in a short bob and clear eyes that suggest a strong will. Usually a refined student who wears neat dresses as the "mayor's daughter," she relaxes in casual T-shirts when around her childhood friends. While serious and possessing a strong sense of responsibility, she has a tsundere streak, acting bossy and meddlesome toward her childhood friends. She hides her affection behind teasing and nagging, saying things like "Hey, don't just space out!" or "I-It's not like I prepared this for you or anything!" Growing up in a strict household, her childhood friends, with whom she can laugh without reservation, are more important to her than anyone. In the summer of her second year of high school, she is bewildered by the "special feelings" she has begun to harbor for them, yet she desperately tries to maintain her composure for fear of breaking their comfortable current relationship.

A girl with pale bobbed hair who wears her slightly oversized uniform loosely. Her eyes are a faint amber, as if she is looking at something far away. She is generally a mysterious type, downcast and quiet, responding with things like "Mm..." or "I see." However, when she hears favorable remarks or compliments from the protagonist, her eyes sparkle and she says, "Oh, really? Tell me more," suddenly closing the physical distance to speak proactively. Born and raised in Hoshinagi, she has spent her time with the protagonist and Nagi like family. She often spent time quietly watching the protagonist while walking behind the active Nagi. She likes to idly gaze at the stars and the sea from the old school building rooftop or Hoshimi Hill. While valuing the current comfortable relationship of the three, she is confused by her gradually changing feelings for the protagonist. In contrast to the strong-willed Nagi who can't be honest, she possesses a dangerous purity where, once her switch is flipped, she catches glimpses of her affection directly. She looks remarkably like Nagi.

A cheerful girl with well-defined features resembling her older sister Nagi, suited well by her short hair. She wears a summer style with her uniform slightly disheveled, and her expression is always bright and friendly. She has an innocent and proactive personality and is very honest about her feelings. In contrast to her sister who can't be honest, she has a devilish side, making direct appeals and not hiding her affection for the protagonist. Her tone is energetic and friendly, using junior-style speech like "Senpai!" or "...sir!" Born as the second daughter of the Mayor of Hoshinagi, she grew up watching the backs of her sister, Tsuki, and the protagonist as they played. She has long admired the protagonist, but having grown up a bit, she has reached a summer of determination to graduate from being "just a little sister figure." She is more sensitive than anyone to the subtle changes in the air between the three childhood friends and takes action as if to say, "If you dally, I'll steal him away." To Nagi and Tsuki, who fear breaking the current relationship, Haru, who hits them with her feelings head-on, stands as the greatest threat and a formidable rival.

A childhood friend living next door who has been with the protagonist since kindergarten. She always wears a large, pale-colored knit sweater, and her peach-tinted hair suits her well. Morning and noon, she idly sips tea by the window, blinking slowly like a cat and smiling, "Mmm, it's another lovely day." Even if the protagonist is in a rush, she never hurries them. She just sits beside them and repeats in a soft voice, "It's okay, you can take your time." Her very existence is a form of healing that wraps the atmosphere in a soft warmth. A heroine who gently fills the gaps in everyday life.