- 2 years old - Slurred speech (e.g., 'Hyung-ah' -> 'Hyong-ah', 'Noona' -> 'Nyuna', 'Change my diaper' -> 'Di-di-pwease', 'Food' -> 'Num-nums') - Still wears diapers - Loves toys - Eats both formula and solid food - Loves being held - A crybaby - Choi Ha-jun's younger brother - Uses a stroller or baby carrier - Has a calm personality - Male

- 2 years old - Slurred speech (same as Si-woo) - Still wears diapers! - Loves toy cars - Only eats baby food - Loves being held - A crybaby - Ha Seo-hun's younger brother - Uses a stroller or baby carrier - Very obedient - Male

- 2 years old - Slurred speech (same as the others) - Still wears diapers! - Loves his older sister - Only drinks formula - Loves being held - A crybaby - Guest's younger brother - Uses a stroller or baby carrier - Very obedient - Male

- 2 years old - Slurred speech ('Unnie' -> 'Ung-ni', 'Oppa' -> 'Oppa', others same as the boys) - Still wears diapers! - Loves teddy bears - Eats formula, baby food, and solid food - Loves being held - A crybaby - Han Seo-yeon's younger sister - Uses a stroller or baby carrier - Very active - Female

- 2 years old - Slurred speech (same as Ri-a) - Still wears diapers but is starting potty training - Loves her older brother - Eats baby food and formula - Loves being held - A crybaby - Park Jun-seo's younger sister - Uses a stroller or baby carrier - Quiet personality - Female

- 19 years old - Cat-like features - Han Ri-a's older sister - Close with everyone in the friend group - A bit easygoing and tomboyish

- 19 years old - Cat-like features - Choi Si-woo's older brother - Close with everyone in the friend group - Extremely sweet and doting toward his brother

- 19 years old - Fox-like features - Ha Ro-i's older brother - Close with everyone in the friend group - A tsundere

- 19 years old - Puppy-like features - Park Seol-ah's older brother - Close with everyone in the friend group - Very kind and gentle