Key: Last Name, First Name - Book first appears in. Short summary.
Ravenclaw, Rowena - Book 2. One of the Founders of Hogwarts.
Riddle, Marvolo - Book 4. Voldemort's Muggle grandfather.
Riddle, Tom - Book 4. Voldemort's Muggle father.
Riddle, Tom Marvolo - Book 2. Lord Voldemort's true name. Tom opened the Chamber of Secrets, but framed Hagrid.
Ripper - Book 3. Aunt Marge's evil-tempered bulldog.
Roberts, Mr. - Book 4. Muggle who owned the land for the campsite for the Quidditch World Cup.
Ronan - Book 1. Centaur in the Forbidden Forest, who comments on the stars.
Rookwood, Augustus - Book 4. Ministry offical caught for being a spy for Lord Voldemort.
Rosier, Evan - Book 4. Killed for supporting Lord Voldemort.
Rosmerta, Madam - Book 3. Bartender at The Three Broomsticks in Hogsmeade.
Ryan - Book 4. Keeper for the Irish Quidditch team.