Arata Minami is a popular male student who attends the same school as the protagonist, Kuroe Akaishi. He is frequently described as a handsome and kind boy who does not fit the typical cliches associated with good-looking characters in romantic comedies. His popularity extends beyond the school campus, as he receives offers to work as a model. This outside attention becomes a recurring element in his life, drawing public and media interest toward him.

Arata's personality is characterized by a genuine and caring nature. He takes a sincere interest in Kuroe, who is largely treated as an outcast by their peers, and this interest is not a cruel joke but comes from a place of authenticity. His own experience with being in the spotlight has shaped his perspective; he reveals that he wants to step away from constant attention and has worked to change himself, including losing a significant amount of weight, to become the person he is known as today. This background gives him a unique empathy for Kuroe's own struggles with her self-image and social standing. Despite his popularity, he is portrayed as being unconcerned with maintaining a flawless public image, a trait that further distinguishes him from superficial stereotypes.

Within the story, Arata serves as the primary love interest for Kuroe, and his actions are the catalyst for much of the plot. By paying attention to Kuroe and eventually dating her, he upends her isolated existence and forces her to confront her feelings and her secret. His presence is a source of both immense joy and tremendous stress for Kuroe, as her powerful emotions for him are directly linked to her involuntary transformations into a giant kaiju. A significant part of their relationship dynamic involves a series of misunderstandings, largely stemming from the fact that Arata is initially unaware of Kuroe's true nature as a monster. He is also confused by her sometimes contradictory behavior, which she employs to hide her condition. As the series progresses, his relationship with Kuroe draws media attention, leading to him being dubbed the Kaiju Prince by the press, which forces him to keep his distance from her to protect her from scrutiny. This development creates new tensions and emotional challenges for the couple.

Arata's most significant relationship is with Kuroe Akaishi. He is also connected to other characters through her, such as Koutarou Hibino, Kuroe's protective uncle figure, who once made Arata jealous by being mistaken for a potential rival for Kuroe's affection. Arata himself is an object of jealousy for many of the other girls at school, who cannot understand why he is attracted to Kuroe. In terms of his own development, Arata is shown to be someone who has already undergone a personal transformation by changing his physical appearance and achieving popularity, but his character arc deepens as he navigates the complexities of a relationship with someone who harbors a profound, world-altering secret. He does not have any notable supernatural abilities; his primary attributes are his good looks, his kind and patient personality, and his status as a popular figure, which ironically becomes a complicating factor in his romance with the reclusive Kuroe.