Arisa Kazuki is a supporting character in the series, known primarily for being the older sister of Tsukasa Kazuki. She is a young woman of notable beauty, possessing fair skin, long grey hair that reaches her upper back with a distinctive chest-length strand on the right side, and silver eyes. Her appearance is often described as strikingly attractive, to the point where another character comments that legendary good looks seem to run in her family.

Arisa's personality is defined by her kindness and unwavering support for her younger brother, Tsukasa. She has a protective nature that stems from their shared past, as she has previously shielded him from their father and from Yukana Kishi, a stalker who had been harassing Tsukasa. This history has made her deeply mindful of his trauma, and her actions are consistently aimed at his well-being. While she has a playful side and enjoys teasing both her brother and Anzu Hoshino, the protagonist, she is careful never to be overly pushy or cross any boundaries, always keeping Tsukasa's difficult past in mind.

Within the story, Arisa serves as a supportive figure for her brother and looks favorably upon Anzu. She is aware of the emotional scars Tsukasa carries from his stalker ordeal and acts as a source of stability in his life, in contrast to the strict father they have had to deal with. Her home is also where Tsukasa goes to live, marking a significant change from his previous living situation. Through her actions, Arisa helps to provide a sense of security for Tsukasa as he navigates his new friendships and confronts his fears. Her relationship with Anzu is positive, as she seems to approve of Anzu's influence on her brother and enjoys lightheartedly teasing the pair about their dynamic. Her notable abilities are not related to combat or magic but lie in her emotional strength and her capacity to act as a protector and confidante, having successfully helped her brother escape from a dangerous and traumatic situation in the past.