How Does Credence Fit Into This Story?
The Blood Pact alone suggests that there are significant gaps in Rita Skeeter's version of the Dumbledore history. The final scenes of Fantastic Beasts: The Crimes of Grindelwald reveal that there's another major omission. Credence Barebone being Aurelius Dumbledore appears to be unrecorded in wizarding history - and even Rita Skeeter seems to have missed it. How does Credence fit into the story of Grindelwald's rise to power, and indeed his ultimate defeat?
So far, all that can be said for certain is that Grindelwald views Credence as the ultimate weapon against Albus Dumbledore. It's unclear whether or not Grindelwald knew who Credence really was when he first traveled to New York in Fantastic Beasts and Where to Find Them, or if he instead discovered the truth of Credence's family history later. The latter option seems more likely, given Grindelwald didn't even know how old the Obscurus he was seeking in New York was. If that's the case, Credence is an even more potent weapon than the dark wizard ever dreamed; the teen is powerful enough to battle against Albus Dumbledore, and the family ties may give him pause.
Credence has stood at the center of both Fantastic Beasts films to date, and this five movie Harry Potter prequel series appears to be as much his story as Newt Scamander's. That means there will no doubt be a lot more twists in his tale; Rowling is a master storyteller, and she delights in complex and sophisticated plans. It also means Credence will probably be part of that final battle between Albus Dumbledore and Gellert Grindelwald in 1945.
Did Aurelius Dumbledore Really Defeat Grindelwald?
The scene in which Grindelwald reveals Credence's true identity is a fascinating one. First, he tells Credence about the origin of the Dumbledore family's phoenix in their time of need; that comment, and the phoenix's very presence, are clearly intended to reassure viewers that Grindelwald is telling the truth about Credence's identity. And then the dark wizard finally discloses Credence's true name: Aurelius Dumbledore. Although audiences have understandably focused upon the surname, shocked at the idea of another Dumbledore sibling, Fantastic Beasts 2 lays equal weight upon Credence's first name of Aurelius. That in itself may form a significant clue as to the character's future.
J.K. Rowling has always enjoyed using word-play when she names her characters, and in the case of "Aurelius" it's interesting to note that there are two famous figures in history who shared that name. The first, appropriately enough, is the Roman leader Marcus Aurelius. Historical records about Marcus Aurelius are complex, just as wizarding history doesn't know what to make of Credence. The second is the British war leader Ambrosius Aurelianus, a 5th century King of Briton. Geoffrey of Monmouth combined tales of Aurelianus with the prophet Myrddin Wyllt in order to create the legendary wizard Merlin. Rowling has long drawn upon Arthurian legends for inspiration, so it's not surprising to find this kind of connection.
Dumbledore is essentially the Merlin figure of the Harry Potter franchise. It's therefore entirely possible that, just as with Ambrosius Aurelianus and Myrddin Wyllt, wizarding history will unwittingly combine the two Dumbledores. In other words, it's possible that Rita Skeeter was on to something; Albus Dumbledore may not have actually been the wizard who defeated Grindelwald in battle at all. Instead, it could well be his younger brother, Aurelius, who bests Grindelwald in combat - and is presumably fatally wounded, explaining why he then disappears from the history books altogether. At this stage, it's difficult to predict exactly why Dumbledore would choose to hide his brother's very existence, let alone his involvement in Grindelwald's defeat; that said, Dumbledore is naturally secretive, and he's always done his best to shield the remnants of his family from further scandal. The revelation that he had an illegitimate brother who was key to Grindelwald's rise to power would certainly be the kind of scandal he'd want to avoid.
If this is the case, then the Fantastic Beasts story has the potential to be a whole lot more surprising than anyone had ever expected. Rather than simply telling a familiar story, and bringing matters to their anticipated conclusion, Rowling has further twists and turns in mind. Meanwhile, this would add a new, poetic element to the Harry Potter story, assuming that Fawkes is the phoenix at Aurelius's side, Albus Dumbledore will inherit the bird, and every time he sees it, he will remember his brother's heroism. This would be a smart way to bind the Fantastic Beasts and Harry Potter franchises together, and it would essentially transform Fawkes into Credence's legacy.