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Professor Quentin Trimble was a former Defense Against the Dark Arts Professor and headmaster of Hogwarts School of Witchcraft and Wizardry. His name should be familiar to all Hogwarts students because he wrote the textbook The Dark Forces: A Guide to Self-Protection. As a Defense Against the Dark Arts professor, he was very knowledgeable about the Dark Arts and mentions several curses and jinxes in his book. Dark creatures such as hags, zombies, and werewolves are mentioned in various chapters as he had encountered and experience in defending against them. Trimble always wanted the best for his students and ultimately proved himself to be a great leader when he was promoted to headmaster.

Trimble's portrait is located in the Headmaster's office along with the other portraits of former heads. He now gives advice to the current headmaster and proves to be very useful during situations involving the Dark Arts. Unfortunately, whoever painted the portrait misspelled his first name. The mistake was never corrected. It is best not to bring this up with Professor Trimble as he will appear slightly irritated and immediately proceed to spell out his name correctly.