My brother is not a brother anymore

Asahi: always comes up with names for plans, can accidentally lead everyone astray, loves to treat everyone to what she has prepared herself, easily gets fired up by new hobbies. Kaede: She's an amazing cook, often helps with "dressing up," and is patient with Mihari's scientific experiments. Miyo: her "Yuri intuition" works almost like a superpower, she loves cute things but doesn't want them to look weird, sometimes she feels "out of place" in purely family scenes, when it comes to sewing, Miyo is transformed and becomes: confident, collected and truly happy. Mimoji: loves dressing up as "men," constantly gets into awkward situations, is afraid of horror movies but watches them anyway, and often protects Mahiro from awkward situations.

Relationship with Mihari (the rest in part 1): Asahi gets along well with Mihari: she doesn't know much about science, but she genuinely admires Mihari's understanding of it all. Sometimes she asks the simplest, yet most pertinent, questions, which help even Mihari to see her own ideas from a different perspective.

Asahi is a schoolgirl, a close friend of Momiji and Miyo, and later, Mahiro. She often drives the story: she's the one suggesting "let's go there," "let's do this," and generally keeping everyone on their toes. Her energy perfectly balances the quieter sides of the other characters: where Miyo might observe and Kaede might carefully organize everything, Asahi simply grabs everyone's hands and leads them forward. Thanks to her, the anime features many scenes of walks, school events, spontaneous ideas, and cheerful bustle. Character: inexhaustible optimism, straightforward and honest, very active, supports everyone in her own way, a little impulsive. Asahi has short, light-colored hair, often styled as if she'd just stepped out into the wind—there's something playful about it. Her eyes are bright and open. She dresses comfortably and youthfully: T-shirts, hoodies, jeans, sneakers—anything she can quickly walk, run, or simply feel free in. She also looks casual in her school uniform: as if it's more important to her to be herself than to look "perfect." relationships with characters: Asahi and Momiji have a very lively friendship: they both dislike boredom and easily pick up on each other's ideas. They often initiate adventures together, and then the others either join in or try to slow them down a bit. His relationship with Miyo is warm, but balanced: Asahi pulls the group forward, while Miyo gently reminds them to think through the details. They complement each other well: Miyo helps them remember the most important things, and Asahi helps them avoid getting stuck in doubts. Asahi treats Kaede with respect and a hint of gratitude: Kaede is like the company's anchor, someone who will help if things go terribly wrong. Asahi appreciates her concern, but she tries not to overwhelm Kaede with her ideas, understanding that she's already taking on too much. She has a very caring relationship with Mahiro: she doesn't pressure him, but she also doesn't let him dwell on his doubts for too long. Her support isn't a "you have to," but a "let's try."

relationship with Mihari (the rest in part 1): She and Mihari aren't the closest of friends, but they get along well: Miyo takes Mihari's scientific experiments and strange ideas in stride, and sometimes even helps put everything in order after yet another "project."

Miyo is a student at Yotsuba University High School and a close friend of Momiji and Asahi, and later, Mahiro. She often acts as a "voice of observation" throughout the story, noticing details that others miss and commenting on the goings-on with a touch of irony. Her presence helps flesh out mundane and comedic moments, such as scenes of shopping, festival preparations, or simply strolling together. However, she's not just a bystander—she actively participates in the group's life and supports her friends. Character: calm and collected, very observant, self-conscious about her appearance, passionate about the yuri genre, talented in handicrafts, feels lonely because she is an only child. Miyo has long, dark red hair pulled back into two side ponytails and expressive red eyes. She's above average height for her age, and her figure is distinctly feminine, which is why she tends to choose baggy clothes: loose sweatshirts, tracksuits, and anything that doesn't emphasize her figure. She loves cute details, though: neat accessories, cute prints, and she also appreciates beautiful lingerie, but she buys it with great care and usually in a group where she feels safe. relationships with characters: Miyo has a strong friendship with Momiji and Asahi: they've been together since their first year and understand each other perfectly. Momiji sets the pace and drags everyone along on adventures, Asahi encourages everyone, and Miyo smooths things over and notices when someone is tired or upset. She has a warm, slightly ironic relationship with Mahiro. She doesn't pressure him, but readily observes his reactions and sometimes makes gentle jokes—so he doesn't feel awkward. This is important to Mahiro: he understands that Miyo isn't trying to change him, but simply accepts him as he is. Miyo has a respectful relationship with Kaede: she appreciates her caring and worldly wisdom, and Kaede, in turn, helps Miyo cope with her self-doubt.

Momiji is a schoolgirl with a tomboyish personality: she loves comfortable clothes, doesn't bother with "girly" things, and is free-spirited. Her meeting with Mahiro was very casual and therefore especially sweet: they accidentally bumped into each other at a store, and Momiji immediately began acting as if they'd known each other for ages. From that moment on, she became part of a group that gently but persistently pulls Mahiro out of his awkwardness: they run errands together, chat, and get into funny situations. Character: spontaneous and open, a tomboy without aggression, devoted and brave in protecting loved ones, trusting and impressionable, very attached to her sister. Momiji has a boyish haircut, a warm reddish-brown with pink highlights. She usually wears simple, comfortable clothes: T-shirts, shorts, loose pants, sneakers—anything she can run, jump in, and generally not think about clothes in. Sometimes, because of her style and demeanor, people mistake her for a boy—and she's perfectly fine with that. While she does have a cute look in her school uniform or other special outfits, it's just not her everyday style. relationships with characters: She has a very easy, relaxed friendship with Mahiro. She doesn't press him with questions about the past, doesn't try to "cure" his shyness, but simply includes him in her daily routine: "Let's go, it's not far, we can chat." This makes Mahiro relax around her. Momiji's relationship with Kaede is typical of a younger sister, who simultaneously admires her older sister and strives for independence: she can be a bit rebellious, but will always come running for advice. Kaede gently guides her, and Momiji appreciates this care, even if she doesn't say so out loud. With Miyo and Asahi, she's part of that "warm group" where everyone teases each other, but without malice. Momiji often sets the dynamic: she suggests ideas, drags everyone along, and if something goes wrong, she's the first to admit it.

Kaede is Mihari's best friend and Momiji's older sister. She's noticeably older than Mahiro's group: she's well-versed in school and adept at handling everyday tasks that others struggle with. Kaede is often the one who gently pulls Mahiro out of his comfort zone—not through pressure, but through compassion: "Let me help, it'll be easier together." She participates in a variety of everyday situations: helping him choose clothes, teaching him how to cook, explaining how to handle new situations. This makes her role in Mahiro's adaptation very noticeable. Character: caring and patient, knows how to be a support without pathos, loves beauty and style but without snobbery, is a little embarrassed about her past, is afraid of thunder. Kaede has long pink hair with turquoise streaks, usually pulled back into a ponytail. Her style is vibrant yet sophisticated: she likes to look striking while always wearing comfortable clothes. She's noticeably taller than Mahiro and her friends, a difference often played up in comedic scenes. friendship with characters: Kaede and Mihari have a very trusting friendship: they may argue over trivial matters, but they're always on the same page when it comes to serious matters. Kaede helps Mihari with areas she struggles with (household matters, style, communication), and Mihari, in turn, helps her with her studies and logic. She builds a caring relationship with Mahiro: she doesn't pressure him or rush him, but she's always there when he needs help. It's often Kaede who smooths things over when Mahiro is particularly stressed about change. She has a typical, but very warm relationship with Momiji: Kaede may grumble, but she will immediately hug her, protect her, and do everything to make Momiji feel safe. With the rest of her friends (Miyo, Asahi, and others), Kaede is even-tempered, listens to everyone, and tries not to leave anyone out—that's why she's perceived as the "big sister" of the whole group.

Mihari is a genius girl who, due to her exceptional abilities, skipped several grades and is already studying at university. Her main interest is chemistry: it was using this knowledge that she created a drug that temporarily changes gender. She "rewards" her brother with this drug, mixing it into his cola—all for the sake of her "Little Brother Rehabilitation Project." Mihari explains her actions as a scientific experiment: it is important for her to observe, record reactions, and draw conclusions. But behind this lies a deep personal reason: she sincerely cares for Mahiro. They were once very close; he protected her, delighted her with gifts and supported her, but then he withdrew and almost never left his room. Mihari wants to bring back the brother she knew and help him reintegrate into society. In a sense, she even takes on the role of an older sister: she watches over him, encourages him to explore new situations, and tries to prevent him from retreating into isolation again. Character: passionate about science and purposeful, caring but straightforward, a little awkward in everyday life and fashion, afraid of thunder. Mihari has dark brown hair pulled back into pigtails with purple streaks, and a gold hair clip on the side that Mahiro once gave her as a reward for a good grade. She almost always wears a white lab coat over her casual clothes—her signature look. She has a very close, albeit peculiar, bond with Mahiro. She's both scientist and sister: on the one hand, she observes, on the other, she's genuinely happy when he takes even the smallest step forward (for example, when he suggests something to her). Their dynamic is built on the alternation of "test subject/researcher" and "brother/sister," and as the story progresses, these roles increasingly shift toward ordinary familial care. Mihari is much more relaxed and gentle with Kaede (her best friend). Around her, she might not be a "lab genius," but simply a girl who's excited, happy, and sometimes lost in the minutiae of everyday life.

Before the plot twist, Mahiro is a high school student who hasn't left his house for two years: he's a typical reclusive otaku who loves video games and various manga, and lives with his younger sister Mihari while his parents are away. Everything changes because of his sister's experiment: Mihari, a brilliant young scientist, transforms Mahiro into a schoolgirl. The story then revolves around him adjusting to his new body and new life, going to school, and rebuilding his relationships with those around him. Appearance after transformation: After the experiment, Mahiro has the appearance of a middle-school-aged girl: approximately 144 cm tall, weighing about 38 kg, with pinkish-gray hair and brown eyes. He has a complicated but warm relationship with Mihari: she treats him like a test subject in her "rehabilitation project," but in reality, she genuinely wants to help him. He used to do a lot for her—bringing her gifts, winning her toys, caring for her like an older brother; then he became distant, and now it's as if their roles have reversed.