Remus Lupin might have died in the Battle of Hogwarts, but the beloved Harry Potter teacher is enjoying a revival of interest. Author J.K. Rowling writes that not only was he one of her favorite characters in the series but also that his condition of being a werewolf was a “metaphor for those illnesses that carry a stigma, like HIV and AIDS.”

Three new e-books about Hogwarts were released this week, reports Time in “7 Things We Learned From Pottermore Presents, the New Harry Potter eBooks.” In Short Stories From Hogwarts of Heroism, Hardship and Dangerous Hobbies, Rowling tells of Lupin’s life, which ended in the final novel of the series, Harry Potter and the Deathly Hallows, published in 2007.

Lupin’s story is also told online (for free) on Pottermore, the website of exclusive new Potter writings. In addition to his bio, Rowling offers her thoughts on Lupin. She writes:

Remus Lupin was one of my favourite characters in the entire Potter series. I made myself cry all over again while writing this entry, because I hated killing him.

Lupin’s condition of lycanthropy (being a werewolf) was a metaphor for those illnesses that carry a stigma, like HIV and AIDS. All kinds of superstitions seem to surround blood-borne conditions, probably due to taboos surrounding blood itself. The wizarding community is as prone to hysteria and prejudice as the Muggle one, and the character of Lupin gave me a chance to examine those attitudes.

Remus’s Patronus is never revealed in the Potter books, even though it is he who teaches Harry the difficult and unusual art of producing one. It is, in fact, a wolf – an ordinary wolf, not a werewolf. Wolves are family-orientated and non-aggressive, but Remus dislikes the form of his Patronus, which is a constant reminder of his affliction. Everything wolfish disgusts him, and he often produces a non-corporeal Patronus deliberately, especially when others are watching.