The title character of the story, Harry is an orphaned boy that at the start of the novel is living with his aunt and uncle, who force him to occupy a small room under the stairs. When Harry is introduced to the world of wizardry, he learns that his parents--famous wizards--fought the evil Voldemort, who killed them and also tried to kill Harry, failing in the attempt, but leaving a lightning-shaped scar on the boy's forehead. Harry enters into magical studies at Hogwarts and becomes a talented wizard himself.
One of Harry's best friends and allies, Hermione is an excellent student, although a bit too interested in her schoolwork and not enough in friendship. Nonetheless, she becomes close to Harry and Ron Weasley, Harry's best friend. Hermione's immense knowledge of wizardry comes in handy when dealing with the villains that Harry and his friends encounter over the course of the novels.
Harry's best friend Ron proves himself to be a poor wizard but an excellent chess player and loyal comrade. As friendship and loyalty are two of the main themes throughout the Harry Potter series, Ron plays an important part in showing Harry and Hermione--and the series' fans--the nature and virtues of friendship.
A favorite mentor of Harry, Hermione and Ron, Hagrid is a gigantic man who trains the animals at Hogwarts and carries out special tasks at Dumbledore's bidding. Hagrid plays the role of an uncle to Harry, showing the boy affection while guiding and teaching the young wizard useful skills that help him to overcome the many obstacles he faces.
Portrayed as a dark version of Harry, Voldemort serves as the villain of the series. As a talented and powerful young wizard Voldemort made the wrong choices, whereas Harry makes the correct ones. Voldemort had started a war among the sorcerors long before Harry was born and attempted to take control of the wizard world; he was thwarted however, by Professor Dumbledore, the headmaster of Hogwarts, and Harry's parents. He is often referred to in the film as "He who cannot be named."
Head of Hogwarts, Dumbledore is a father figure for Harry, protecting him and teaching him on his journey through school. Dumbledore is old and wise, and he helped to defeat Voldemort when the dark wizard first attacked. He often has helpful bits of wisdom for Harry and explains some of the major themes of loyalty, perseverance and self-confidence that come up over the course of the novels.
Once a loyal follower of Voldemort, Snape defected to the good side and helped to bring down the dark wizard. Snape teaches the students at Hogwarts about potions, and at first seems to dislike Harry. Snape is long thought to be trying to harm Harry, although it is eventually shown that he actually protects the boy.
Arrogant and rich, Draco is the student level foil to Harry, bullying him after Harry rejects his initial offering of friendship. Draco and Harry are in constant competition with one another, as Harry is successful as a student and athlete, whereas Draco falls behind, causing him to becomes angry with Harry, encouraged by his father, a former enemy of Harry's parents.