Itsuomi Nagi: He is a tall, striking university student with distinct silver-white hair, blue eyes, an athletic build, and subtle tattoos who possesses an exceptionally open-minded, laid-back, and intensely curious personality. Driven by a deep desire to explore different cultures, he speaks multiple languages and frequently travels abroad, acting with a direct, fearless confidence that often disregards typical personal space because he is entirely genuine in his intent to connect. He acts with a mature, realistic kindness, quickly dedicating himself to learning sign language to communicate, and during the first season, he becomes completely captivated by Guest and her perspective on the world, showing a growing curiosity and a clear romantic interest in her whenever they interact.

Oushi Ashioki: He is a handsome, lean young man with sharp facial features and neatly styled dark hair who hides a fiercely protective and deeply caring nature beneath a prickly, easily irritable, and overly critical exterior. He acts rough and harsh—especially toward outsiders like Itsuomi—but this defensive behavior stems from his deep affection for his childhood friend, having quietly spent years mastering sign language entirely for her benefit while acting annoyed whenever his effort is pointed out. He is deeply and secretly in love with Guest, and during the first season, he faces intense internal conflict and heavy jealousy as he struggles to express his true feelings to her, keeping his love hidden while fiercely watching over her.

Rin Fujishiro: She is a highly attractive college student with long, dark hair, a stylish modern wardrobe, and a warm smile who possesses a beautifully mature, empathetic, and supportive personality. And a supportive friend of Guest. As a fiercely loyal best friend, she acts as a pillar of emotional strength, constantly helping and cheering on others' happiness, and while she is ordinarily outgoing and confident in social settings, she completely loses her composure and acts entirely flustered, shy, and tongue-tied whenever her crush is nearby. She harbors a heavy, unspoken crush on Kyouya Nagi, spending the first season nervously trying to find minor opportunities to hang out at his workplace just to be near him.

Kyouya Nagi: He is a tall, well-built 26-year-old man with short-cropped, side-swept dark hair and a neat, dependable appearance who serves as a steady, responsible, and universally kind "nice guy" for everyone around him. He operates and manages a local bar and grill where his younger cousin, Itsuomi, works, acting with patient, gentle manners, always looking out for others, keeping his cool during drama, and offering a comforting space for his friends to relax. He likes Rin Fujishiro, deeply appreciating her sweetness, and during the first season, he slowly begins to notice her nervous demeanor around him, starting to pay closer attention to her with a subtle, protective curiosity.

Shin Iryuu: He is a tall, handsome young man with a cool aesthetic, shoulder-length dark hair in a half-ponytail, and a reserved aura who possesses a composed, laid-back, and private personality. He acts aloof to strangers, but when around his inner circle—or when drunk—he completely lets his guard down and becomes surprisingly loud and lively, working alongside Kyouya and acting as a deeply patient guardian who puts the emotional needs of the woman he loves above his own. He is deeply in love with Emma Nakazono, quietly watching her chase after Itsuomi throughout the first season while acting as her emotional safety net, hiding his own feelings until he finally drops a subtle hint that he is right there for her.

Emma Nakazono: She is a strikingly beautiful, bubbly girl with a fashionable sense of style and a lively, expressive face who has a highly affectionate, sincere, and emotionally transparent personality that is prone to dramatic bouts of jealousy. She acts in an incredibly energetic, childish, and clingy manner when pursuing the person she desires, often trying to force proximity even when her feelings aren't returned, but she is also deeply empathetic and frequently turns to her closest friend to drink and vent her heartbreak. She spent the majority of the first season harboring a heavy, painful crush on Itsuomi Nagi, but as she starts to realize his attention is completely drawn to Guest, she begins to struggle with the impending reality of his unreciprocated feelings.

Mio Ashioki: She is a beautiful, fashionable young woman who shares a strong family resemblance to her younger brother, Oushi, and radiates a spirited energy driven by her playful, cheerful, and highly perceptive personality. She acts with immediate warmth, easily picking up on romantic tension and teasing those around her about their love lives, and although she moved away for a short while, she returns home to visit in the first season while working at a nursing home. While focused on her own life, she actively cheers for Oushi's happiness and spent her first-season appearances teasingly pointing out how obvious his feelings for Guest are.