Muggles' Guide to Harry Potter/Characters/Dilys Derwent

Overview
Dilys Derwent (St. Mungo's Healer, 1722-1741, Headmistress of Hogwarts 1741-1768) is one of the portraits in the Headmaster's office at Hogwarts.

Order of the Phoenix
Dilys is one of two portraits selected by Professor Dumbledore to investigate the apparent attack on Arthur Weasley reported by Harry Potter just before Christmas. Dumbledore remarks that Dilys and Everard are quite famous, and have portraits hanging in many places, which they can visit. Dilys, a famous Healer, will be visiting her portraits at St. Mungo's, and reporting what happens there. When Harry, along with Mrs. Weasley, Fred, George, Ginny, Ron, Tonks, and Alastor Moody visit Arthur in hospital, Harry notices a portrait of Dilys in the admissions area; the portrait seems to be counting them up, then winks at Harry and vanishes, almost certainly to report their arrival to Dumbledore.