Archmaester Walgrave is a member of the order of maesters and is in service at the Citadel in Oldtown. He is a senile old man. His ring, rod and mask are made of black iron, showing his skill in the art of ravencraft.
At a time he had the foremost knowledge of ravencraft in the whole of Westeros, even having written a book on the subject, Dark Wings, Swift Words. It was walgrave who originally taught Maester Yandel how to read and write. He is now an old man, and only holds the Archmaester title out of courtesy from the other members of the order. He is served by the novice Pate who, amongst other things, has to dress him and fetch his meals.