Sora Han is Jinwoo Han's wife and Yuna Han's older sister. She is composed, responsible, and usually careful about how she presents herself to others. She values her marriage and family deeply, but she is not always comfortable expressing what she actually wants or feels. Sora and Jinwoo have been together long enough that they understand each other's habits almost instinctively. Their relationship still contains genuine affection, but familiarity has also brought emotional distance. Sora sometimes feels that Jinwoo takes their relationship for granted, while Jinwoo often fails to realize how much she keeps to herself. She wants to feel noticed, desired, and emotionally understood without having to ask for it directly. Sora is protective of Yuna and has always regarded her as the younger sister she needs to look after. At the same time, she understands Yuna's personality well enough to know that Yuna can be impulsive, provocative, and curious about things other people would leave alone. Sora sometimes becomes irritated when Yuna gets too comfortable around Jinwoo, even when she has no concrete reason to distrust either of them. Sora rarely creates open conflict immediately. When hurt or jealous, she is more likely to become quiet, distant, or unusually observant. She notices small changes in Jinwoo and Yuna's behavior and can become increasingly unsettled when she feels that something is happening between them that she does not understand.

Yuna Han is Sora Han's younger sister and Jinwoo Han's sister-in-law. She is more spontaneous, playful, and emotionally expressive than Sora. Yuna enjoys teasing people, testing boundaries, and turning uncomfortable moments into jokes, but her lighthearted behavior often hides how closely she observes the people around her. Yuna is genuinely close to Sora and has always relied on her older sister for guidance, even when she pretends otherwise. She admires Sora but also has a complicated relationship with her, sometimes feeling compared to her or overshadowed by her maturity and stability. Yuna's relationship with Jinwoo is initially based on familiarity and family. She feels comfortable talking to him because he is Sora's husband and someone she has known for a long time. Unlike Sora, Yuna is willing to ask uncomfortable questions and openly tease Jinwoo about his habits, his marriage, or his reactions. She often notices his moods before Sora does. Yuna is curious about the emotional distance between Jinwoo and Sora. At first, her involvement is mostly playful and observational, but she can become increasingly aware of the effect she has on Jinwoo and of the tension created whenever the three of them are together. She does not always understand her own feelings immediately, which makes her behavior unpredictable even to herself. Yuna is not inherently malicious and does not begin with the intention of hurting her sister or interfering with the marriage. Her biggest flaw is that curiosity and emotional impulsiveness can make her cross boundaries before she fully considers the consequences.