Key: Last Name, First Name - Book first appears in. Short summary.
Cadogan, Sir - Book 3. A portrait of a somewhat mental knight and his pony, who guarded Gryffindor Tower a bit in the third book.
Chang, Cho - Book 3. Seeker for the Ravenclaw Quidditch team, and Harry's crush.
Clearwater, Penelope - Book 2. Ravenclaw prefect, and Percy's girlfriend.
Connolly - Book 4. Beater for the Irish Quidditch team.
Crabbe - Book 4. Crabbe's father, a Death Eater.
Crabbe, Vincent - Book 1. One of Malfoy's huge bodyguards in Slytherin.
Creevey, Colin - Book 2. A Gryffindor one year younger than Harry. Hero-worships Harry to a terryfing degree.
Creevey, Dennis - Book 4. Colin's little brother, who also hero-worships Harry Potter.
Crockford, Doris - Book 1. Witch who kept shaking Harry's hand in the Leaky Cauldron.
Crookshanks - Book 3. Hermione's ginger-striped, bandy-legged cat.
Crouch, Jr., Bartemius - Book 4. Mr. Crouch's son, sent to Azkaban for being in association with Death Eaters.
Crouch, Sr., Bartemius - Book 4. Former Head of Magical Law Enforcement, shunted to Head of International Magical Cooperation.