J.K. Rowling’s world of witchcraft and wizardry isn't without its real-life influences. Although the characters in her Harry Potter series are all fictional, the author did draw upon a few key traits from some real-world personas to create some of those fan favourites.

Aunt Marge borrowed from her grandmother

Remember Aunt Marge, Uncle Vernon’s sister who insults Harry and his late parents until he loses control of his magic and blows her up bigger than Violet Beauregarde in Charlie and the Chocolate Factory? She, too, takes particular inspiration from Rowling's life: her grandmother Frieda who is described as having preferred “her dogs to human relatives,” much the way Aunt Marge seems to in her brief but memorable scenes in Harry Potter and the Prisoner of Azkaban.

Natalie McDonald was a real girl who made it onto the page

Little Natalie McDonald deserves a mention here. In Harry Potter and the Goblet of Fire, there's a throwaway line about how Nearly Headless Nick was delighted to hear that House Gryffindor's newest recruit was one “McDonald, Natalie,” and while that might not seem significant on its own, the backstory of this namedrop is very meaningful. Rowling's literary reps were approached by the family of a nine-year-old girl battling leukemia who a Harry Potter fan, and Rowling responded with a note. "Jo's email was beautiful." Little Natalie didn't live long enough to read the books, and Rowling would later include McDonald's name in her book as a bit of honor to the girl who believed in magic.

The dementors are drawn from her own past

Before she became an author, J.K. Rowling had more than her share of struggles. As she has recalled many times, including in her address to Harvard University graduates in 2008, she wrote the series from what she described to be “rock bottom,” a point in her life when she was a poor single mother with few prospects for success. Writing about the Boy Wizard's travails was her avenue of release. She suffered through deep depression during those times, and that experience with facing her own demons would later manifest in the dementors which were used to imprison exiles in the Harry Potter series. In a 2000 interview with The Times UK, she admitted, "It was entirely conscious. And entirely from my own experience. Depression is the most unpleasant thing I have ever experienced.”