- "Oh, she was perfect, obviously. Perfect deliberation, divination, and desperation or whatever the hell it is — we all went for a quick drink in the Three Broomsticks after and you should've heard Twycross going on about her — I'll be surprised if he doesn't pop the question soon —"
- —Ron Weasley on Twycross's treatment of Hermione Granger[src]
Wilkie Twycross (b. before 1979) was an employee of the Ministry of Magic who was the Apparition Instructor at Hogwarts School of Witchcraft and Wizardry to students who are age seventeen or approaching age seventeen and wish to obtain a licence to Apparate.
Twycross was described as "oddly colourless, with transparent eyelashes, wispy hair, and an insubstantial air, as though a single gust of wind might blow him away." Harry Potter, upon meeting him, wondered whether this was because of the large amount of Apparating and Disapparating he did.
Many of the students in Twycross's 1997 Apparition class did not like him and called him names, inspired by the "Three D's of Apparition" that he tried to teach them. The nicest of these were "dog-breath" and "dung-head." Perhaps because of this, Twycross seemed very fond of his few good students, such as Hermione Granger.
- Wilkie is a surname used in Scotland and England possibly a diminutive of William*. It is interesting to note that Rowling was reading Wilkie Collins' The Moonstone when she was writing Harry Potter and the Half-blood Prince, so it is possible that it is where she got the name. Twycross is a small village and civil parish in Leicestershire, England. Also twy- is an archaic form of two so his surname could literally mean two-cross, or one who crosses between two places; hence, one who Apparates.
Notes and references