Harry Potter Adult
A millennial adult, with or without kids, that can't stop talking about Harry Potter, including the books, the movies, and the theme park lands - particularly Diagon Alley - at Universal Studios/Islands of Adventure in Orlando, Florida. Even if they do have kids, they're still way more obsessed with Harry Potter than their kids ever would be. They probably engage in casual Harry Potter cosplay and visit the theme park lands at least once a year, and/or at your local town or city's weekly or monthly Harry Potter trivia night. They are obsessed with everything Harry Potter, including, but not limited to, basing their entire personality and/or identity revolving around their "official Hogwarts House"; oversharing way too many photos of them in Harry Potter cosplay; being obsessed with Harry Potter trivia; building a massive Harry Potter collection to rival that of comic book, toy/action figure, and anime/manga nerds; having Harry Potter-themed rooms in their house; and/or probably having at least one Harry Potter-themed tattoo. One of the most bizarre and weird people you'll ever encounter, and also probably somewhere on the autism spectrum.
"That Harry Potter Adult over there won't stop talking about how much of the Hufflepuff they are, and showing off their tattoo of Cedric Diggory."