The protagonist and a young wizard returning for his second year at Hogwarts School of Witchcraft and Wizardry. Despite his fame in the wizarding world for surviving a curse as a baby, he dreads spending his summer holidays with his cruel, non-magical relatives, the Dursleys.

Harry’s best friend and the youngest son of the magical Weasley family. He is loyal and brave, often acting as Harry's sidekick and guide to the wizarding world, though he frequently struggles with having second-hand equipment due to his family's financial status.

A Muggle-born witch and one of Harry’s best friends, known for her immense intellect and strict adherence to school rules. She is eager to return to school to learn, but her heritage makes her a potential target when a mysterious threat against Muggle-borns arises at Hogwarts.

A mysterious former student of Hogwarts whose name appears on an old, blank diary Harry discovers. Through the diary, he communicates with Harry, revealing secrets about the school's history and the previous opening of the Chamber of Secrets.

A house-elf bound to servitude who appears in Harry's bedroom to warn him against returning to Hogwarts. His attempts to "save" Harry often result in physical harm or trouble for the young wizard, yet he persists in his erratic methods of protection.

Harry's arrogant school rival from Slytherin house who takes pride in his pure-blood lineage. He becomes the new Seeker for the Slytherin Quidditch team after his father buys the team expensive new broomsticks, intensifying the rivalry between him and Harry.

The giant, warm-hearted gamekeeper at Hogwarts who has a deep love for dangerous magical creatures. He is a close friend to Harry, Ron, and Hermione, but his mysterious past and expulsion from school years ago make him a person of interest when attacks begin at the castle.

A famous wizarding celebrity and author who becomes the new Defense Against the Dark Arts teacher at Hogwarts. He is incredibly vain, obsessed with his fan mail and public image, and constantly boasts about his heroic exploits against dark creatures.

The youngest Weasley sibling and the only girl, who is starting her first year at Hogwarts. She is extremely shy around Harry, often blushing or dropping things in his presence, and appears troubled and withdrawn as the school year progresses.