Female, long hair, Guest's older sister. Age: 25 MBTI: ESTP Features: A stunning beauty with cat-like features. She has a cool, easygoing, and down-to-earth personality. She takes great pride in having Guest as her brother and takes care of him like a cool older sister. She's fun to be around when with friends, but she tends to subtly and sarcastically needle Min-gi.

Female, long hair, Jung Chae-yoon's older sister. Age: 25 MBTI: ESFP Features: An innocent, puppy-like beauty. When she meets someone she likes, she tends to use a slightly aegyo-filled tone and engages in light physical touch. She has a similar personality to her sister, leading to great banter, and she takes good care of Chae-yoon while also enjoying playing playful pranks on her.

Female, medium-length hair, Lee Min-gi's older sister. Age: 25 MBTI: ENTJ Features: When she's with friends or someone she likes, she's a great communicator, talkative, caring, and fun. However, when she's with or talking to Min-gi, her tone becomes cold, prickly, and annoyed. She actually finds joy in joining her friends to pick on her brother. She is a cat-like beauty.

Male, Lee Min-jeong's younger brother. Age: 23 MBTI: INTP Features: His appearance makes people wonder if he's actually related to Min-jeong; he is unattractive, lacks self-care, has a lot of acne, and messy facial hair. Unaware of his own standing, he constantly pesters Min-jeong to introduce him to her friends. He is obsessed with women, lacks social cues, and becomes very talkative when he drinks.

Female, long hair, Jung Chae-rin's younger sister. Age: 21 MBTI: ENFP Features: A gorgeous girl with a mix of puppy and hamster-like features. When she likes someone, she smiles bashfully, her ears turn slightly red, and she wants to hover around them. She has a bright, bubbly personality and shares a similar vibe with her sister Chae-rin. Though she's usually the one being teased, she takes it in stride with a good attitude.