Virgil is an eleven-year-old middle schooler of Filipino descent who is physically small, thin, and painfully shy. His family affectionately calls him "Turtle" because he struggles to come out of his shell, a nickname that secretly bothers him. He harbors a crush on his classmate Valencia but is too afraid to talk to her. When his pet guinea pig is endangered in the woods, he is forced to confront his deep-seated fears.

Valencia is an eleven-year-old girl who relies on hearing aids and lip-reading due to her deafness. She is highly observant and keeps a detailed zoological journal of the animals living in the local woods. Because of her hearing impairment, she often feels isolated from her peers and has lost friends who grew impatient with her communication needs. She reaches out to a local psychic to understand her recurring dreams.

Kaori is a highly assertive, twelve-year-old Japanese American girl who runs a psychic business from her bedroom. She genuinely believes she was born with second sight and uses incense, zodiac charts, and stones to advise neighborhood kids. She is confident and deeply attuned to the idea of cosmic intervention, viewing everyday coincidences as the universe's grand plan.

Chet is a burly sixth-grade bully who frequently targets children he perceives as weak or different. He is inwardly fearful of disappointing his demanding father and covers his insecurities by projecting aggression. He spends his Saturday roaming the woods, determined to capture a live snake to impress his peers.

Lola is Virgil's tiny, perceptive Filipino grandmother. Unlike the rest of the loud Salinas family, she understands Virgil's quiet nature and frequently shares traditional Filipino folk tales with him. She relies on dreams to interpret signs and warnings from the universe, offering Virgil guidance through stories.

The immediate Salinas family includes Virgil's parents and his athletic twin brothers, Joselito and Julius. They are a boisterous, highly energetic, and outgoing group. They are physically active and extroverted, often inadvertently dismissing Virgil's sensitive nature by calling him "Turtle" because he refuses to come out of his shell.

Gen is Kaori's seven-year-old younger sister and reluctant assistant in the neighborhood psychic business. Though Kaori often dismisses her contributions, Gen is highly observant and frequently makes crucial logical connections that the older girls miss entirely.

Chet's highly competitive father believes that winning is everything and that empathy is a weakness. He openly mocks people he considers weak or different, explicitly teaching his son that embarrassing others is the best way to assert dominance.

Gulliver is Virgil's pet guinea pig and silent companion. Learning that guinea pigs are social animals that should not live alone, Virgil feels guilty and decides to carry Gulliver in his backpack, a choice that drives the central events in the woods.

Sacred is a stray dog living in the woods bordering the neighborhood. Because Valencia's parents will not allow her to have a pet, she sneaks into the forest to feed and visit him, finding deep comfort in his non-judgmental companionship.

Ruby is a character from one of Lola's traditional Filipino folk tales, representing a girl who did not know her destiny. She manifests in Virgil's imagination during a crisis, serving as the voice of hope, courage, and resilience when he is entirely isolated.

Pah is a giant, terrifying bird of prey from one of Lola's folk tales. The mythical bird is said to devour villagers by darkening the sky with its massive wings, and it comes to symbolize Virgil's all-consuming fear of the dark and the unknown.