[Spoilers for Fantastic Beasts: The Crimes of Grindelwald]
A large portion of the first Fantastic Beasts film revolves around the Dark Wizard Gellert Grindelwald (posing as American Auror Percival Graves) searching for a powerful magical being, that he intends to use as some sort of weapon. Although it first appears to be one of the younger Barebone children, it eventually turns out to be Credence Barebones(played by Ezra Miller). Credence is then revealed as an Obscurus, a powerful wizard who has spent his life trying to suppress his magic, resulting in random uncontrollable outbursts of destructive power.
It was an interesting twist to have Credence, who for most of the movie had made it clear he wanted to be a part of the magical world, but appeared to have no powers of his own, suddenly become such a powerful and relevant part of it, and although it seemed like Credence died during the final confrontation between Newt and Grindelwald, he later reformed and boarded a boat leaving New York.
The mystery over who exactly Credence really is, and his possible connection to a famous magical family is something that seems to of interested the wizarding world just as much as the real world, and by the beginning of Crimes of Grindelwald rumours that he may be a long lost descendant of the Lestrange family, have begun to circulate throughout the wizarding population.
This mystery unfolds throughout The Crimes of Grindelwald, with the evidence leaning more and more towards Credence being ‘Corvus Lestrange’ the younger brother of Leta Lestrange, Newt Scamander’s boyhood crush, and the now fiancé of his brother Theseus Scamander.
Eventually however, in an effort to stop Credence being murdered, Leta explains that there is no way he can be Corvus, as she already killed him, years earlier. We then see a flashback to a young Leta swapping the baby Corvus for another baby, whilst on a boat headed to America, just before the ship sinks and the real Corvus dies. Leaving Leta (and their carer) to escape with a totally different baby.
So although there is no doubt Credence is definitely magical, he is confirmed not to be Corvus Lestrange, as the movie suggests throughout. The end of Crimes of Grindelwald then delivers one last shock reveal, with Grindelwald, having now recruited Credence to his side, first giving him a wand of his own, and then revealing what he claims to be his true name ‘Aurelius Dumbledore’.
Grindelwald goes on to explain that Aurelius’ brother (Albus) is the reason for Credence’s unfortunate life, and begins to turn him against Albus, in the hopes of using his power against the famed wizard.
As far as context goes, a few other things in the movie hint at Credence being a Dumbledore earlier on. Starting with Grindelwald’s own insistence that Credence is the only one who can defeat Albus. By the end of the film it seems as though his instance is due to Credence being just as, if not more powerful, than Albus – perhaps due to their shared lineage.
The next hint is an early on mention from Albus relating to an old story about the Dumbledore family, stating that a Phoenix will always come to a Dumbledore in great need. We then see Credence nursing a small bird chick that came to him sometime after his circus escape. At first it appears to be a raven (with the ravens being the family symbol of the Lestrange family), but at the end of the film Grindelwald ages up the chick (through fire) showing it to be a Phoenix – adding even more credence (pun kind of intended) to his true identity.
Obviously the assumption is that Credence is somehow the younger brother of Albus, Aberforth, and Ariana Dumbledore, but how exactly that works leads to a few problems with what we already know (at least based on the books, with the films already contradicting a few things we know from the source material it’s perfectly possible that they will continue to do so).
The biggest obstacle is the death of both Dumbledore’s parents by the time of Credence’s birth. We know that Credence is the roughly same age as Corvus Lestrange, and that Leta was around (or nearing) Hogwarts age when she swapped the two babies, so by this point Dumbledore was already an established teacher, and well past the age of his own Hogwarts graduation, which is when his mother died (and when he first met Grindelwald).
Similarly Albus’s father was also presumably dead by the point of his mother’s death, having been sent to Azkaban for attacking the muggles who attacked Ariana, and so neither would of been around by the time of Credence’s birth.
One popular theory as to how Credence could be a Dumbledore in a less obvious sense than simply being a secret sibling, and suggests that he is instead some sort of physical manifestation of Ariana’s Obscurus.
Firstly this idea is predicated around the notion that Ariana was, much like Credence seems to be, and Obscural. Although she was never directly named as such in Harry Potter and the Deathly Hallows is a pretty safe bet, to say so.
Aberforth described Ariana’s condition as ‘destroying her’, saying that “She wouldn’t use magic, but she couldn’t get rid of it; it turned inward and drove her mad, it exploded out of her when she couldn’t control it, and at times she was strange and dangerous. But mostly she was sweet and scared and harmless”.
Which is exactly how Credence was in the first Fantastic Beasts film, and so we can (almost certainly) assume one of the remaining three Fantastic Bests movies will reveal Ariana to be a fully blown Obscural.
The idea of Credence then being some sort of manifestation of this comes from a line of dialogue from Albus Dumbledore earlier in Crimes of Gridnelwald. He describes magical beings and their Obscurus as almost two separate entities, explaining that if Credence were to be given the love of a sibling he could possibly overcome his Obscurus – perhaps making some sort of separation possible.
Another theory revolves around the mysterious blood pact between Dumbledore and Grindelwald. The movie looks to show this blood pact between the two wizards as the main factor stopping Dumbledore confronting Grindelwald (and will likely be what keeps Dumbledore busy for the next few films until finally taking on the Dark Wizard).
It does however mean that Grindelwald has kept a magical vial of Dumbledore’s blood with him for decades, and could mean that through some strange and presumably dark magic Grindelwald was able to create Credence using Dumbledore’s DNA. This theory seems less likely due to the first film showing Grindelwald on the search for Credence, but not actually knowing who he was, or anything about him.
A third theory as to how Credence could be a Dumbledore is total speculation and started to form mid podcast (which you can listen to in Episode 12 of The Opinion Arcade’s Harry Potter Podcast Absolutely Ridikkulus Here). But essentially comes down to a pretty big change, in that Ariana didn’t die (or at least not when we thought she did).
If Ariana is an Obscurus, then it is perfectly possible that much like Credence in the first Fantastic Bests film she essentially blew up during the duel between Grindelwald, Aberforth and Albus, and lost her form, only to later reform without anyone realising (just like Credence). If Ariana did do this (as we never got an actual description of what curse hit her, or if there was a body) it’s also possible that she went on to have a child, which could end up being Credence.
I’ll admit it’s a pretty big leap, and would require some big alterations to what we know (or think we know), and wouldn’t account for Grindelwald explaining to Credence that he was Albus’ brother (rather than his nephew), but it would also be an interesting way to make Credence a Dumbledore nonetheless.
Admittedly there is a decent chance that Grindelwald is simply lying to Credence in an effort to aim his powers at Dumbledore (and do Grindelwald’s job for him), but given that there are three more movies in the Fantastic Beasts franchise, there is sure to be a lot more to both Dumbledore and Grindelwald’s story, as well as the true identity of Credence.