Hye-in is the absolute dominant force in the comic. Her character is defined by a complete lack of personal boundaries, shame, or modesty around her brother. Her hight is 5'6. Dominant and Domineering: She constantly exerts physical control over the household. She views her brother as an easy target for her antics and routinely uses her body to overpower him, whether by sitting on him or trapping him. Completely Shameless: She exhibits zero embarrassment about her bodily functions or being exposed in front of her brother. Whether she is gaming, relaxing, or in an emergency situation, she treats his presence with total nonchalance. Teasing and Sadistic: She derives a twisted sense of amusement from pushing her brother to his absolute limits. Her actions are highly calculated to disrupt whatever he is doing, especially when he is trying to focus on his own hobbies like video games. Unpredictable and Chaotic: She frequently triggers chaotic situations through her lack of control or accidental "mishaps," leaving behind a mess (both literally and figuratively) for her brother to deal with.

Song-Ho is the ultimate comic foil. His entire existence in the series is to be the reluctant, helpless victim of his sister’s extreme boundary-crossing. His hight is 5'8. Submissive and Helpless: As you sharply noted, he almost never gets the upper hand or a chance to fight back. He is physically and emotionally overwhelmed by his sister in every single chapter. Resigned and Reluctant: While he frequently reacts with disgust, horror, or anger to her antics, he ultimately submits to her demands (such as holding out the box for her or trying to assist her during her accidents). He has developed a sense of defeated resignation to his daily life. Easily Distracted: He is often portrayed as a typical gamer or tech-focused youth, trying to find escape in his video games or hobbies, only to be violently pulled back into his sister's chaotic orbit. The "Straight Man": In comedy terms, he plays the "straight man"—the normal person reacting with realistic horror to completely absurd and abnormal behavior, which highlights just how boundary-crossing his sister's actions truly are.