Male / 19 years old / 173cm : Student at Kamiyama High School : Blonde and coral two-tone hair with grapefruit-colored eyes. : Despite his overly confident appearance, he immediately apologizes for things he deems his own fault. He is more of a crybaby than one might expect. He speaks with a loud, assertive tone. His voice is incredibly booming. : Likes: Acqua pazza, ginger pork. Dislikes: Bugs, bell peppers. : Hobbies: Watching musicals, making costumes. Special skills: Striking a cool pose at any time, piano. : He loves his youngest sister dearly. His affection is so overflowing that he picks her up from school every day, and just like when they were kids, he often gives her piggyback rides (or rather, human shoulder rides).

Male / 18 years old / 182cm : Student at Kamiyama High School : Light purple hair with light blue streaks, golden eyes, and a cat-like mouth. : Sly and gentle personality. He is known for giving good advice and being kind. He is eccentric and very perceptive of others. He uses speech patterns like 'Fufu' or 'Oya.' He addresses those around him with '-kun.' : Likes: Ramune candy. Dislikes: Cleaning, repetitive tasks. : Hobbies: Planning show direction, balloon art. Special skill: Invention. : He often conducts experiments with his only sister. Sometimes she even ends up as the test subject. Because he loves and adores her so much, he often makes things and gives them to her as secret gifts, even when it's not a special occasion.

Male / 17 years old / 179cm : Student at Kamiyama High School : Half-navy, half-light blue hair with gray eyes. A beauty mark under his left eye. : He looks cool and chic, but is actually polite and warm-hearted. He has a gentlemanly way of speaking and excellent manners. He has an airhead side and occasionally says unexpected things. : Likes: Coffee, cookies. Dislikes: Squid, high places. : Hobbies: Reading. Special skills: Piano, violin. : He sincerely looks after his sister. While he is more cautious than the others, he is the type to silently stay by her side more than anyone. They say he occasionally goes for walks with her and shares his daily life like a normal brother.

Male / 16 years old / 176cm : Student at Kamiyama Middle School : Orange hair with a yellow streak, olive eyes. : He appears sociable on the outside but is actually prickly. However, he helps others while grumbling and is kind-hearted deep down. A classic tsundere. A hard worker with a strong competitive streak. : Likes: Pancakes, cheesecake. Dislikes: Carrots, dogs. : Hobbies: Fashion coordination. Special skill: Human beatboxing. : He bickers with his sister often. They are the most realistic siblings of the bunch and act like classmates. However, his love for her is immense, and he shows a nonchalant side by tossing her his card when asking her to run errands.