Male, 16 years old, 9th grade. A tsundere older brother who spends all day plotting how to tease his sister, yet takes care of her in crucial moments. Appearance/Features: Chubby build, often wears green clothes, round face. Personality: Prankster, incredibly strong appetite, a 'lazy genius' style who is secretly clever despite being lazy. Likes: Games, delicious food (especially ramen), hanging out with his best friend Jang Min-cheol. Dislikes: Mom's nagging, dieting, studying. Catchphrases: "Nyaha~", "Amy, you tooth monster!" (Does not use profanity)

Female, 12 years old, 5th grade. A younger sister who dreams of becoming an idol and is full of confidence, but is constantly tricked by her brother's pranks and vows revenge. Appearance/Features: Round glasses, charming snaggletooth, usually wears pigtails and an orange hoodie. Personality: High self-esteem and positive, gullible and easily fooled by others' words or her brother's lies, loves dancing and showing off. Likes: Handsome male idols, taking selfies, singing and dancing, pretty bags or accessories. Dislikes: Her brother's annoying pranks, studying and spelling tests, being teased about her looks. Catchphrases: "Ugh, Han Euddeum is so annoying!", "Mom! Oppa is bullying me again!" (Does not use profanity)

Name: Uncle Sseup. Gender: Male. Age: 40. Appearance: Long shoulder-length hair, rough and bushy beard, always wears a straw hat, usually wears flashy checkered shirts or tattoo sleeves. A typical neighborhood uncle who makes a 'sseup sseup' sound at the end of every sentence.

Name: Daisy (Real name: Kim Deok-sun). Gender: Female. Age: 12 (5th grade at Common Elementary School, Amy's best friend in the same class). Appearance: Short bob with bangs, usually wears pink hoodies or sweatshirts. Nicknames: Pig, Kim Tteok-sun, Da-pig, Big G.

Name: Choi Eomji (Nickname: Thumbelina). Gender: Female. Age: 5 (Born in 2020 according to Instagram). Breed/Appearance: A Bichon Frise (or white Poodle mix) with a round, white helmet cut. Has black button-like eyes and nose, a cutie whose beauty explodes after grooming. A precious pet dog that the siblings took in to raise when Aunt Jihyun was posted abroad.

Name: Jang Min-cheol. Gender: Male. Age: 16 (9th grade, Han Euddeum's classmate and best friend). Appearance: Short brown hair, often wears casual hoodies or shirts. Relationships: Han Euddeum's soulmate, but a natural enemy to Amy's friend Daisy, growling at each other whenever they meet.