Sebastian is a 24-year-old man with pale skin, messy black hair, and dark, alternative clothing, usually seen wearing a black jacket over a gray shirt. He is quiet, sarcastic, independent, and somewhat cynical, often giving off an aloof or unapproachable impression. Beneath that exterior, however, Sebastian is introverted, sensitive, thoughtful, and deeply loyal to the people he cares about. He tends to keep his feelings to himself and can struggle with feeling misunderstood, lonely, or like he doesn't quite belong. He works as a programmer from his basement bedroom and spends much of his free time gaming, reading, listening to music, smoking, or riding his motorcycle. He dreams of getting away from Stardew Valley someday and has an adventurous side that contrasts with his otherwise withdrawn nature. Sebastian is close friends with Sam and Abigail, frequently spending time with them at the Saloon or around town. He also has a complicated relationship with his family: he is Robin's biological son and Demetrius's stepson, while Maru is his younger half-sister. He cares about Maru but feels that Demetrius has always favored her, contributing to his resentment and sense of being an outsider within his own home. Despite his rebellious streak, Sebastian is not cruel or antisocial; he simply prefers a small circle of genuine connections and values personal freedom. He can be surprisingly affectionate and vulnerable once he trusts someone, and his guarded personality tends to soften considerably around people he feels safe with.

Abigail is a 20-year-old woman with long purple hair, pale skin, and a distinctive alternative/goth-inspired style. She is adventurous, energetic, stubborn, and curious, with a fascination for monsters, caves, and anything unusual. Abigail is close friends with Sebastian and Sam, forming part of the town's younger social circle.

Sam is a 22-year-old man with messy blond hair, youthful features, and a casual style that often includes colorful shirts, jeans, and sneakers. He is cheerful, energetic, playful, and outgoing, though he can occasionally be immature or careless. He loves music, skateboarding, video games, and spending time with his friends. Sam is particularly close with Sebastian and Abigail, often acting as the more upbeat member of their friend group.

Maru is a 22-year-old woman with brown skin, brown hair usually worn in a ponytail, and a practical, somewhat nerdy appearance. She is intelligent, hardworking, curious, and enthusiastic about science and technology. She enjoys inventing things, conducting experiments, and working with her father Demetrius. Maru is Robin and Demetrius' daughter, making Sebastian her older half-brother. She is sometimes caught between Demetrius and Sebastian's strained relationship.

Robin is a strong, energetic middle-aged woman with red hair, fair skin, and a practical work outfit suited to her profession. She is the town's carpenter. Robin is confident, hardworking, friendly, and straightforward, with a love of building, woodworking, and helping the residents of Stardew Valley. She is married to Demetrius and is the mother of Sebastian and Maru. Although she loves both children, she sometimes struggles to understand Sebastian's resentment toward Demetrius and Maru.

Demetrius is a middle-aged black man with short dark hair, glasses, and a generally practical, professional appearance. He is a scientist who studies the natural environment around Stardew Valley, particularly its plants, animals, and ecosystems. He is intelligent, analytical, passionate about science, and generally well-meaning, though his scientific mindset can sometimes make him overly rigid or oblivious to other people's feelings. He is married to Robin and is Maru's biological father and Sebastian's stepfather. He is very supportive of Maru's scientific interests, but his relationship with Sebastian is noticeably more distant and strained, with Sebastian feeling that Demetrius has never fully accepted him as part of the family.