J.K. Rowling is really sorry about killing everyone’s favorite werewolf. In “Harry Potter and the Deathly Hallows,” Remus Lupin was one of many wizards who lost their lives during the Battle of Hogwarts. On May 2, the anniversary of the fictional fight, Rowling apologized to her Twitter followers for offing the beloved character.

Rowling did the same thing on this day last year. She apologized for the death of Fred Weasley. “I thought I might apologise for one death per anniversary. Fred was the worst for me, so I started with him,” she tweeted to a fan. She followed through with that promise.

Apparently, the decision to kill off Lupin was made several years before Rowling even began writing the 2007 installment. She revealed that the decision was made while she was writing 2003’s “Harry Potter and the Order of the Phoenix.” Interestingly, Lupin and Sirius Black were the last surviving best friends of Harry’s parents (if you don’t count the traitorous Peter Pettigrew). Black was killed in “Order of the Phoenix,” but Rowling didn’t talk about this link.

She instead discussed a more unexpected connection. Lupin died because Arthur Weasley lived. She explained that since the Weasley clan was able to keep their patriarch, the Lupin family had to lose theirs. The former Defense Against the Dark Arts teacher died in the Battle of Hogwarts alongside his wife, Nymphadora Tonks. Like all “Potter” deaths, theirs were tragic, but the loss was even more upsetting because they left a newborn behind. Teddy Lupin grew up without a family, and Rowling admitted that detail brought her to tears.

Teddy Lupin’s childhood might be a story fans get to see eventually, though. “Harry Potter and the Cursed Child,” the two-part play that premieres this summer, will pick up 19 years after Harry defeated Voldemort. Harry’s children will be a focus of the show, so it doesn’t seem like an appearance from Teddy would be out of the question. Of course, Rowling, who wrote the story along with Jack Thorne and John Tiffany, hasn’t wanted to give away too many details. “Cursed Child” begins previews at the Palace Theatre in London on June 7 and officially opens in July.