With Fantastic Beasts: The Crimes of Grindelwald hitting theaters this weekend, Harry Potter fans are about to be introduced to even more characters, family members, and hidden connections revealed in the new movie. There's a lot going on in Crimes, from a familial prophecy, to a growing cult-like organization, to how Newt's beasties fit into all of the plot points. Major spoilers ahead! But one big shocker comes at the end of the film, and it's one that might retcon the family lineage of our favorite future-headmaster, Albus Dumbledore. In fact, it's revealed at the end of Crimes that one of the other major characters was born Aurelius Dumbledore. But wait, a minute, did Dumbledore have another brother?
Of course, we know of one brother: Aberforth Dumbledore. He appeared in a few of the Harry Potter films and played a big part in Harry Potter and the Deathly Hallows Part 2 when he explained what happened many years prior to drive he and Albus apart. As Aberforth tells it, Albus and Gellert Grindelwald became close (whether they were simply friends or actually in a relationship is something the canon has yet to explicitly explain) but Grindelwald was, let's say, a bad influence on Dumbledore. This led to a showdown between Albus, Aberforth, and Grindelwald that put the Dumbeldores' sister, Ariana in the crossfire.
Ariana was hit with a Cruciatus Curse, but it wasn't clear from whose wand, that of Albus, Aberforth or Grindelwald. But the story of the three Dumbledore siblings ends there. The new movie, however, suggests that there's a third Dumbledore sibling, and Grindelwald's secret plan to find, lure, train, and unleash him against his own family makes up a major plot point of the movie. But who is he? Fantastic Beasts: The Crimes of Grindelwald suggests that Dumbledore's secret brother is Credence Barebone, the obscurial from the first Beasts movie.
Grindelwald uses Credence's status as an outcast and obscurial to lure him to his cause, the takeover of the non-magical world. He tells Credence that his own brother "wants him dead" and that his real name is Aurelius Dumbledore. Now, there are a couple of fishy things going on here. For one, Albus, as played by Jude Law, is significantly older than Credence by about 20 years. It's certainly possible, biologically, that Credence and Albus are brothers, but the Dumbledore parents, Percival and Kendra, weren't exactly in a position to make another child. Kendra had died when Ariana was 14 and Albus about 17. And Percival had already been in Azkaban Prison for many years, having killed the boys who attacked Ariana as a child.
So, is Credence really Albus and Aberforth's long-lost brother? It's not really a 100% certainty. After all, Grindelwad can't exactly be trusted, and he might just be using Credence for his intense powers as an obscurial in order to defeat Dumbledore. (He and Albus can't actually battle one another due to a blood pact they made as young men.)Then again, The Crimes of Grindelwald relies heavily on themes of brothers and brotherhood. Newt and his brother Theseus go through an intense reunion and reckoning having to do with their mutual affections for Leta Lestrange. And Leta herself has a complicated and emotionally fraught backstory involving her own older and younger half-brothers that features a climax on the Titanic (yes, that Titanic).
So it's perfectly possible that Credence is a real Dumbledore brother, though we'll have to wait and see how that's possible in the three (yes three) more Fantastic Beasts movies that are to come. But the biggest piece of evidence that Credence is really a Dumbledore comes via one of those beasts. As Albus explains to Newt in the film, he's always had a fascination with phoenixes because the birds are known to appear to any Dumbledore in need. At the end of the film, a phoenix appears to Credence, AKA Aurelius. It's still possible Grindelwald lured the creature there, but something tells me that the bird, and more beasts, will have a big part in the revelations to come.