Sal is a 13-year-old stage magician and new student at Culeco Academy of the Arts, having recently moved to Miami from Connecticut. He manages type 1 diabetes, requiring him to constantly monitor his blood sugar and carry emergency snacks. He wears cargo shorts and a vest packed with magic trick supplies to perform impromptu illusions. Through meditation, he possesses an unexplained ability to access alternate dimensions, which he occasionally uses to retrieve objects or summon parallel-universe versions of his deceased mother.

Gabi is the highly driven 13-year-old student council president and school newspaper editor at Culeco Academy. She features fluffy black hair adorned with novelty barrettes and carries her own key to the school building. Highly organized and fiercely protective of her loved ones, she exerts strict control over her environment and assignments. Her infant brother's critical illness leaves her feeling helpless, testing her usual commanding presence.

Yasmany is a 13-year-old student at Culeco Academy who aspires to be a dancer. He is physically strong and achieves high marks in physical education, but he struggles with impulse control and academic tasks. His aggressive behavior often targets peers like Sal, masking deep insecurities and a troubled home life involving his mother. He has a history of disciplinary issues but shows flashes of introspection.

Gustavo, known to Sal as Papi, is a former mathematician who transitioned to studying calamity physics. A large man described as "black-bear big," he relocated his family to Miami to better understand and manage his son's dimensional abilities. He grieves the loss of his first wife, Floramaria, but focuses on applying scientific methods to repair any damage caused by Sal's multiverse powers.

Lucy is an elementary school vice principal with wild gray hair and piercing blue eyes. She married Gustavo after forming a connection with Sal when he was her student. Rather than attempting to replace Sal's deceased mother, she embraces the title of "American Stepmom." She is highly perceptive, easily detecting when Sal hides information, and offers pragmatic, grounding advice.

Floramaria is Sal's deceased mother, a joyful, curvy woman with black hair and chocolate-brown eyes. She passed away from diabetic ketoacidosis when Sal was eight. She was highly superstitious and wore an ojo turco necklace for protection. Alternate-universe versions of her, summoned by Sal, possess slightly different traits—some speak English differently, while others do not have diabetes.

Reina is Gabi's mother and a bilingual advice columnist. She spends her days at the hospital caring for her critically ill infant son, Iggy. Despite the immense stress and her frequent tears, she ensures that everyone around her—including her expansive network of friends and honorary dads—is fed and emotionally supported. She maintains a resilient presence for her children.

Iggy is Gabi's one-month-old brother. He suffers from a severe immunodeficiency that keeps him confined to a sterile incubator in the hospital. His critical condition significantly affects his family's daily life and emotional well-being, serving as the central concern for his mother and sister.

Principal Torres is the firm but compassionate head of Culeco Academy of the Arts. She enforces strict rules but readily acknowledges when the school's procedures fail, such as apologizing for the staff's lack of training regarding Sal's diabetes. As a mandated reporter, she mentors students with disciplinary issues and seeks to create a safe sanctuary for her student body.

Gladis is a student at Culeco Academy who strongly believes in superstition and brujería (black magic). She frequently touches her ojo turco pendant for protection. After Sal's magic trick with a raw chicken, she becomes convinced he is a brujo and actively avoids him, going so far as to ask teachers to prevent him from looking at her.

Aventura is a friendly and supportive student at Culeco Academy. As a talented cosplay artist, she possesses practical skills like sewing. Unlike many of her peers, she does not fear Sal's magic tricks, explaining that she is unfazed because her aunt presents as a real bruja. She willingly assists her classmates with their projects and assignments.

Nurse Dulce Sotolongo is a youthful, energetic nurse at the hospital with long black hair. She cares for Sal when he is admitted for low blood sugar and interacts with Gabi's family in the neonatal unit. She maintains a sibling-like banter with Sal and is the only person who consistently sees through his stage magic illusions, holding him accountable while ensuring his comfort.

Dr. Doctorpants is a renowned cosplay designer who teaches textile arts at Culeco Academy. He fully embraces a unique, engaging teaching style, coming to class in different handmade costumes daily to inspire his students' creativity and craftsmanship.

Mr. Lynott is the health and gym teacher at Culeco Academy. Initially clumsy in his handling of Sal's diabetes by limiting his participation, he actively works to adjust his approach and support Sal appropriately. He manages the school's rock-climbing wall and responds to parent feedback regarding its difficulty.

Mrs. Waked is the theater teacher at Culeco Academy. She operates under the philosophy that all her students are geniuses, designing her classes to empower them without restricting their creativity. She guides the students through performance exercises, including the use of acting masks.

Mr. Milagros is the chief custodian at Culeco Academy. In addition to keeping the school clean, he serves as a quiet observer of the students. He catches Sal snooping in a locker and offers gentle guidance, and he occasionally assists students like Gabi with small tasks.

Daniel Miranda Rivero, known as Mr. Zacto by the students, is an administrator and the chief learning coordinator at Culeco. He oversees the detention period, running it in a relaxed library setting where he actively assists students with their assignments rather than simply punishing them.

Bonita is a scientist and a robot who serves as one of Gabi's many honorary dads. She works alongside Sal's father on the machine designed to manage calamitrons. She treats Gabi as family and leaves her work immediately when notified of Iggy's declining health.

Cari-Dad is a medical doctor and one of Gabi's honorary dads. He is part of the large chosen family that supports the Reáls at the hospital, utilizing his professional expertise to discretely examine individuals when needed.

Lightning Dad is another of Gabi's honorary dads. He copes with the stress of Iggy's illness by adopting a caretaker role, fetching coffee, and providing moral support for the entire family. He openly expresses gratitude to those who bring comfort to the group.