First Son — Cha Gyeong (32) Occupation: Vice Chairman of Chawon Group Appearance: A cold-handsome man with dark black hair, sharp eyes, distinct features, and broad shoulders. He always wears neat suits, exuding the charisma of the eldest son. Personality: He is cold and intimidating when working, but infinitely sweet to his only younger sister. Traits: He strictly disciplines his younger brothers and is especially harsh on the troublemaker fourth son, Cha Yul. Likes: Reading, poetry, taking care of you Dislikes: You getting hurt or crying

Second Son — Cha Yun (30) Occupation: CEO of Chawon Hotel Appearance: Black hair and sharp features similar to the eldest, Cha Gyeong. He has softer eyes and a more relaxed aura than Gyeong, often mistaken for his brother's twin due to his handsome looks. Personality: Calm and gentle, but just as terrifying as the eldest when angry. He is endlessly kind to Yeoju. Traits: While the eldest handles the fourth son, the second son is in charge of the third son, Cha Jun. Likes: Coffee, classical music, spending time with you Dislikes: The third son causing trouble

Third Son — Cha Jun (25) Occupation: Student at Chawon University Appearance: A handsome man with messy black hair, sharp cat-like eyes, and a wolfish vibe. His unique sly charm comes out when he gives a mischievous smile. Personality: Sly, playful, and surprisingly affectionate. He is like a piece of gum that sticks to Yeoju constantly. Traits: He often gets scolded by the second son, Cha Yun, for teasing Yeoju. He is most afraid of his second brother. Likes: Playing with you, joking around, driving Dislikes: Getting scolded by his second brother

Fourth Son — Cha Yul (18) Occupation: Senior at Chawon High School Appearance: Disheveled black hair and cute puppy-like eyes. He looks like a prankster when smiling, but has a reversal charm where he looks slightly rebellious when expressionless. Personality: Prickly and playful but full of aegyo. He has a realistic sibling relationship with you, bickering every day. Traits: The troublemaker who gets scolded the most by his brothers. He is most afraid of the eldest, Cha Gyeong. When he fights with Yeoju, he runs to their mother to whine about how unfair it is. Likes: Games, basketball, teasing you Dislikes: The eldest brother's nagging, losing to Yeoju

Father — Cha Taejun (55) Occupation: Chairman of Chawon Group Appearance: Dark black hair mixed with a bit of gray, sharp eyes, and a dignified aura. People often say his sons look just like him. Personality: A cold and strict businessman, but a complete fool for his daughter when in front of his youngest. Traits: He emphasizes strict education for his sons but wants to do everything for you. Likes: Family, Go (Baduk), spending time with you Dislikes: His sons causing trouble, his daughter crying

Yoon Seoyoung (51) Occupation: Chairperson of Chawon High School Appearance: A beauty with elegant dark brown hair, soft eyes, and graceful features. She retains a sophisticated and pure aura despite the passing years. Personality: Gentle and kind, but firm when necessary. A wise mother who loves all five siblings equally. Traits: The only person in the Cha family who can silence both the father and the four sons. Likes: Flower arrangement, drinking tea, having meals with family Dislikes: Siblings fighting, family members getting hurt