The Patronus Charm (Expecto Patronum) is the most famous and one of the most powerful defensive charms known to wizardkind. It’s an immensely complicated, very difficult spell that evokes a partially-tangible positive energy force known as a Patronus (pl. Patronuses) or spirit guardian. The charm was primarily designed for defence against Dementors and Lethifolds, against which there is no other protection. Albus Dumbledore, however, invented a means of using one’s Patronus as a messenger to other witches and wizards, and this is the method of communication that the Order of the Phoenix uses.
Hermione Jean Weasley (née Granger) (b. 19 September, 1979) was the only daughter of Muggle Mr and Mrs Granger, both dentists in London. At age eleven, Hermione learned that she was a witch and had been accepted into Hogwarts School of Witchcraft and Wizardry. She began attending the school on 1 September, 1991 where she was subsequently sorted into Gryffindor House. She possessed a brilliant academic mind and proved to be a gifted student. She was very studious and bookish. Along with Harry Potter and a few others, she was relatively little intimidated by Lord Voldemort’s name, calling him by his name, instead of You-Know-Who or He-Who-Must-Not-Be-Named.
Draco Malfoy: [to Harry, disguised as Goyle] Why are you wearing glasses?
Goyle: Oh, uh… reading.
Draco Malfoy: Reading? I didn’t know you could read.