Micah is a creative 10-year-old boy who lives with his grandfather following the sudden death of his parents. He shares his grandfather's love for tying intricate knots with string and drinking sweet tea. Confronted with his caregiver's severe illness, Micah becomes determined to find a traveling magical circus to secure a promised miracle.

Ephraim is Micah's fun-loving guardian who is currently suffering from a severe respiratory illness. Despite his failing health, he maintains a joyful disposition, playing games with his grandson and rejecting his sister's rigid rules. He carries fond memories of visiting Circus Mirandus as a 10-year-old boy and fully believes in its magic.

Gertrudis is Ephraim's fiercely practical sister who moves in to manage the household during his illness. Known for brewing scalding bitter tea, she despises anything she views as frivolous, actively stripping the house of toys and imposing rigid schedules. She attempts to separate Micah from his grandfather's stories of magic due to a deep betrayal she experienced in her own youth.

Formally known as The Man Who Bends Light, he is a powerful illusionist at Circus Mirandus. With a magically elongated lifespan, he dedicates his existence to nurturing faith and wonder in children. He wears a beaten brown leather coat and creates fully immersive environments for his audience.

Jenny is the highest-achieving student in Micah's class and his assigned partner for a school project. Highly logical and reliant on science, she struggles to comprehend anything that defies rational explanation. She questions Micah's stories about a magical circus but offers practical support during his difficult time.

Chintzy is a magical talking parrot who serves as the Lightbender's personal messenger. She is frequently irritable, complaining about rain and the necessity of traveling through sewer systems to reach suburban homes. She diligently carries out her duties connecting the hidden circus to the outside world.

Known as the Amazing Amazonian Bird Woman, Victoria is a fiercely ambitious former performer shown in flashbacks to the circus's past. As a teenager, she survives a plane crash by discovering she has magical flight. She deeply values fame and grows to resent the circus's focus on entertaining children, desiring greater power and recognition.

Mr. Head is the manager and namesake of Circus Mirandus. He possesses a mysterious ability to grant unusually long health to his performers. He works tirelessly to preserve the fragile nature of childhood faith and fiercely protects his audience from any performers who might abuse their magic.

Rosebud is an enormous circus resident with a pink-painted bald head. She runs a wagon filled with intriguing animals and specialized potions within Circus Mirandus, offering remedies to visitors in need.

Geoffery is the steadfast ticket taker stationed at the entrance of Circus Mirandus. He enforces the circus's unique admission rules, accepting symbolic offerings like fish or knotted strings in place of traditional money.

Obidiah is Ephraim's father, serving overseas in a war during Ephraim's childhood. His prolonged absence weighs heavily on young Ephraim, shaping the boy's early need for the comfort and hope provided by the circus.

Big Jean is an exceptionally smart elephant residing in the menagerie of Circus Mirandus. She is capable of learning complex tasks like tying knots and solving math problems, frequently assisting the performers with transportation.