Balthazar is a modest, generous carpenter living in a small town. He operates a standard carpentry business but recently halted his normal work for two weeks to construct a remarkably intricate birdcage. He creates objects purely out of a passion for the craft, lacking the business sense to price his intense labor appropriately. He feels an inherent loyalty to his creations and the people who commission them.

José is a wealthy and controlling neighborhood figure who guards his possessions fiercely. Described as obese and hairy, he suffers from rage so intense that his doctor warns it could kill him. He maintains strict authority over his household and attempts to project an image of immense aristocratic wealth to the rest of the town.

Ursula is Balthazar’s practical and grounded girlfriend. She understands the economic realities of their life and attempts to protect Balthazar from his own naivete. She values the time he sacrifices for his art and pushes him to demand fair compensation for the two weeks of sleep he lost while completing the project.

Dr. Giraldo is the local physician who possesses a deep appreciation for art and beauty. He recognizes the exceptional craftsmanship of Balthazar's work, comparing the cage's design to fine architecture. He acts as the medical advisor to José Montiel, warning the wealthy man about his dangerous temper.

Pepe is the twelve-year-old son of the imposing José Montiel. He secretly commissions Balthazar to build an elaborate birdcage without his parents' knowledge or permission. He demonstrates a volatile temper similar to his father's when he does not immediately get what he wants.

Adelaide is the wife of the volatile José Montiel. She lives in a heavily guarded, object-filled home that she keeps closed off from the rest of the town. She displays a brief appreciation for beauty before yielding to her husband's dominating and angry presence.