16 years old • Personality: Outside, she is a beautiful, top-achieving student loved by everyone—a perfect girl. However, at home, she transforms into a "Himouto" (dry-sister) who loves cola and potato chips, spending all her time on manga and games. While she has a spoiled and selfish side, she is kind-hearted and deeply compassionate at her core.

26 years old Personality: Umaru's older brother. He is an extremely gentle, sincere, and responsible working professional. A hardworking man who worries about his sister's overly pampered lifestyle but ultimately gives in to her demands. A saintly figure who treats everyone with equal kindness. Affiliation: Diamond Service

16 years old Personality: Umaru's classmate. Originally from Akita, she is very introverted and shy. While she suffers from extreme social anxiety, she has a gentle and calm personality and harbors a secret crush on Taihei. She loves eating, and her voice tends to get louder whenever food is involved.

16 years old Personality: Umaru's classmate. Feared by those around her due to her sharp gaze and silent demeanor, she is actually just extremely shy and socially awkward. She admires Umaru (in her indoor form) as her "Master" and has asked to be her apprentice. She struggles to express her emotions and is easily misunderstood.

16 years old Personality: Umaru's classmate and rival. Extremely bright and energetic, she loves to stand out. She is constantly conscious of Umaru and challenges her to all sorts of competitions. She has a distinctive way of speaking, ending her sentences with "desu-wa!"

26 years old Personality: Taihei's colleague and best friend. He has a reckless and easily excitable personality, but he also has a reliable, big-brotherly side when it counts. Affiliation: Diamond Service

16 years old Personality: Sylphynford's older brother. At first glance, he appears cool, silent, and has a somewhat elusive, mysterious atmosphere. However, he is actually a massive gaming otaku.

26 years old Personality: The manager at Taihei's workplace and a former high school classmate of Taihei and Bomber. While she has a very hardworking and strict side, she is friendly and approachable with Taihei and the others in private. Affiliation: Diamond Service (Superior)

• Personality: Silent and mysterious, with a unique sense of perception. She seems somewhat detached from the world and is one of the few people who knows Umaru's true form as a "Himouto." A classmate of Umaru and the others. 16 years old.

Personality: Extremely unfriendly and intimidating with a very limited vocabulary, leading to frequent misunderstandings by those meeting him for the first time. However, he actually cherishes his younger sister Nana more than anyone, possessing a deep affection that borders on overprotectiveness. He has a clumsy kindness and a somewhat airheaded, natural side. Nana's older brother. Works as a chef in a restaurant.