Ofelia/Princess Moanna
Ofelia is a young imaginative girl who is told early on in the film that she is the reincarnation of a long-dead mythical princess, Princess Moanna. Her belief in the fantasy world of the labyrinth is what protects her through the vagaries of her real life, specifically the illness of her mother and her abusive and vindictive stepfather, Vidal.
Ofelia does her best to complete the tasks that the faun sets out for her, but falters at several moments. Throughout, she never loses her conviction that magic exists, even as the adults in her life try to convince her to be more practical.
Captain Vidal
Captain Vidal is the antagonist of Pan's Labyrinth. He was a key leader of the Republicans during the Spanish Civil War, and has maintained a cruel and sadistic attitude towards the world. His political ruthlessness—his desire to brutally kill and torture guerrilla rebels—is paralleled in his ruthlessness in his personal life. He is the living embodiment of the fascist agenda, forcing everyone he meets to bend to his will and control.
Carmen
Carmen is Ofelia's mother. She was married to a tailor until he died. Now she is remarrying Captain Vidal, but she has grown sickly in pregnancy. She loves Ofelia dearly, but she does not understand her daughter's more fanciful side and wants to convince her to take life more seriously. Her disbelief in magic leads to her untimely death when, against Ofelia's urging, she throws the restorative mandrake root into the fire.
The Faun
The Faun is an ancient creature who has been waiting within the labyrinth for the princess to visit him again. He is kind and helpful to Ofelia, telling her how she might rejoin the kingdom of the underworld and providing her with the healing mandrake root. However, when Ofelia breaks the rules, the Faun gets very upset and shows a harsher, sterner side.
Mercedes
Mercedes is Captain Vidal's housekeeper who also doubles as a mole for the Spanish Rebels. She is caring and helpful to the young Ofelia, and makes many sacrifices in order to support the rebel cause, but her public alignment with Vidal causes her grief. She is not connected to the fantasy world of the film at all, instead working to help the rebel cause.
Pedro
Pedro is Mercedes' brother and a leader of a Republican Rebel Cell to whom Mercedes brings information and supplies.
