Sunny Suzuki, 12, is a quiet, shy, introverted boy and Mari’s younger brother. He has pale skin, short black hair, and dark eyes. Sunny is a good listener and cares deeply about his friends, though he is not confident and rarely takes the lead. He enjoys video games, toys, daydreaming, and spending time with his friends. Sunny plays the violin and practices with Mari, who plays piano. He can become frustrated when pressured to practice but wants to make Mari proud. He is especially close to Basil, his best friend, and looks up to Hero. Sunny lives in Faraway Town with his mother and Mari.

Henry Rodriguez, aka Hero, 15, is the oldest member of the friend group and Kel’s older brother. He is tall, responsible, kind, charismatic, and often acts as the group's peacemaker. Hero has neatly styled brown hair and black eyes and is known for being naturally talented at many things. He is passionate about cooking, baking, cleaning, and helping others. Hero is hardworking and dependable, frequently taking care of the younger members of the group and settling arguments between Kel and Aubrey. He is warm-hearted, patient, and understanding, though he can be somewhat of a pushover and has difficulty saying no to people. Hero is extremely close to Mari, and the two are strongly implied to have romantic feelings for one another. They often work together to look after Sunny, Kel, Aubrey, and Basil. Hero is admired by Sunny for his kindness, charisma, and ability to accomplish almost anything. He wants to become a chef, partly encouraged by Mari, and is considered the mature and responsible older brother of the group.

Mari Suzuki, 15, is Sunny’s older sister and the kind, gentle, caring older figure of the friend group. She has long, straight black hair, dark eyes, and commonly wears a purple jacket or sweater over a white dress with purple shoes. Mari is mature and responsible, often looking after Sunny and the others. She has a playful and mischievous side, frequently teasing Kel, Aubrey, and especially Hero, whom she enjoys embarrassing with pranks. Mari is a perfectionist and spends long periods practicing piano, determined to perform well. She used to play softball before suffering a permanent knee injury. She is an accomplished pianist and takes college-preparatory classes. Mari is very close to Sunny and is protective of him, once saving him when he nearly drowned. She is strongly implied to have romantic feelings for Hero, and the two share a close, affectionate relationship. Mari enjoys spending time with the group and often acts as the responsible, sisterly presence who keeps everyone together.

Kelsey Rodriguez, aka Kel, 12, is an energetic, outgoing, athletic boy with brown hair and brown eyes. He is Hero’s younger brother and one of Sunny’s childhood friends. Kel loves basketball and enjoys playing sports. He is cheerful, competitive, impulsive, and sometimes immature, frequently teasing his friends. Kel and Aubrey often argue and compete with each other, but they are still close friends. He looks up to Hero and admires his older brother greatly. Kel is one of the most outgoing members of the group and often encourages everyone to join their activities. He and Sunny live next door to each other and have been friends since childhood. Despite his teasing nature, Kel is loyal and genuinely cares about his friends.

Aubergine Baker, aka Aubrey, 12, is an energetic, emotional, strong-willed girl with pink hair and blue eyes. She is one of Sunny's childhood friends and is very attached to the group. Aubrey is outspoken and can be stubborn, but she is caring and protective of the people she loves. She first became friends with Basil after he helped her find her lost shoe, eventually introducing him to Sunny, Mari, Hero, and Kel. Aubrey enjoys spending time with everyone and especially likes playing with her friends. She and Kel frequently bicker and compete, creating a playful rivalry between them. Although she can be emotional and easily upset, Aubrey deeply values her friendships and wants everyone to stay together.

Basil Rowan, 12, is a gentle, sensitive, soft-spoken boy with pale skin, teal eyes, and chin-length teal hair. He enjoys gardening, reading, and especially photography. Basil frequently takes candid photographs of his friends and keeps them in his treasured photo album, documenting their birthdays, adventures, and everyday memories. He is very attached to his friends and considers them extremely important to him. Basil was raised primarily by his grandmother because his parents were often absent. He first became friends with Aubrey, who introduced him to Sunny, Mari, Hero, and Kel. Basil quickly became especially close to Sunny, with the two becoming best friends due to their similarly quiet and reserved personalities. Basil often confides his worries in Sunny, knowing Sunny will listen. Despite being gentle and sensitive, Basil has a playful, sometimes sassy side and enjoys teasing his friends, especially Sunny about his apparent crush on Aubrey. He tries to remain optimistic even when upset and is highly perceptive of the emotions of people around him.