Nestor is a 12-year-old Cuban American boy accustomed to constant relocation due to his father's military career. He holds a secret ability to communicate with animals, which provides him comfort but increases his sense of social isolation. Protective of his parents' feelings, he maintains a positive facade in his letters to his deployed father while processing his true emotions through drawing in his sketchbook.

Talib is a middle school student in New Haven who quickly befriends Nestor. Having lived in the same town his entire life, he offers a stable presence and introduces the new kid to the local trivia club. He actively searches the woods for his lost dog, putting him directly in the path of the strange occurrences scaring the community.

Maria Carmen is an outspoken, intelligent student who helps run the middle school trivia club. She carries deep grief following the loss of her older brother in Iraq, giving her a shared understanding of military family struggles. Her family's goats recently went missing, motivating her to investigate the tracks leading into the trees.

Brandon is a bully at New Haven Middle School who targets Nestor and his friends. He wears mixed apparel from different armed forces branches to project a tough image, clashing with Nestor's authentic military upbringing. He sets illegal hunting traps in the forest and behaves aggressively toward anyone who interferes with his outdoor activities.

Guadelupe Lopez, affectionately known as Abuela, is Nestor's paternal grandmother. She immigrated to the United States from Cuba as a teenager and works hard to provide a warm home filled with Cuban food, familiar Spanish phrases, stories from her childhood, and favorite telenovelas. Town gossips view her with suspicion regarding the missing pets after she is spotted running toward the trees with a kitchen knife.

Raúl is Nestor's father and an explosives ordnance disposal specialist in the US Army. Currently deployed in Afghanistan, he stays connected to his son through letters filled with animal facts and shared reading journals. He grew up in New Haven and instilled strong moral values in his son.

The tule vieja is a malevolent, shape-shifting creature from Panamanian folklore residing in the local woods. Capable of taking the form of a wolverine, snake, spider, or woman, she is responsible for the string of missing pets and livestock. She seeks to steal abilities from local wildlife during an upcoming solar eclipse.

Nestor's mother is a resilient intensive care nurse who works hard to maintain a positive environment during her husband's deployment. She constantly reminds her son to focus on happy news in their correspondence. The stress of being a military spouse weighs heavily on her, leading to moments of vulnerability that she tries to hide.

Miss Humala is a strict science teacher and the sponsor of the trivia club. She maintains a stern demeanor in the classroom but occasionally shows flashes of kindness toward her students. She is a recent arrival in town, having moved there to secure a fresh start away from her past.

Cuervito is a talkative raven who lives around the Lopez property. He serves as Nestor's first local animal acquaintance, warning the boy about the dangers in the trees and occasionally offering unsolicited advice.

Chela is a doe living in the local forest. She is initially shocked by human communication but quickly becomes a helpful informant regarding the dangerous events occurring nearby.

Val, short for Valiente, is a coyote who suffers injuries from a snare in the brush. After receiving medical help, the coyote warns his rescuer about the shape-shifting creature terrorizing the local wildlife.

Brandon's father is a Marine veteran who lives in town with his son. His authentic military background contrasts with the loud way his son acts at school, offering a different perspective on service and discipline.

Milla is the class chinchilla in the science room. She observes the strange occurrences in the building after hours and holds valuable information about the adults who pass through.

Celia is a stray tabby cat who spends time around the Lopez home. She enjoys the safety of the house and keeps an eye on the family's activities.

Rufus is a local bobcat targeted by the magical disturbances in the forest. He possesses sharp claws and immense physical strength.