Rubeus Hagrid is a teacher and groundskeeper at Hogwarts, friend of Harry, Ron,and Hermione. He is also a "half-giant." His father was not a giant, whereas his mother, who died whilst he was young, was a giant. He has a half-brother named Grawp. In the movies, Hagrid is played by Robbie Coltrane.
Hagrid was expelled from Hogwarts after The Government thought he had opened the Chamber of Secrets, but he had been framed by Tom Riddle and so was allowed to remain at the school as gamekeeper. Hagrid is also friends with Madame Maxime, it is not known if they were together in a romantic way.