It's revealed in Fantastic Beasts: The Crimes of Grindelwald that Albus Dumbledore and Gellert Grindelwald created a Blood Pact when they were younger, and it's theoretically possible that the Blood Pact could be destroyed by using dragon's blood, something that Dumbledore is known for discovering in the Harry Potter franchise.

Throughout Fantastic Beasts 2, Dumbledore refuses to go after Grindelwald, and it's only later revealed in The Crimes of Grindelwald's ending that the reason the two couldn't fight each other is because their Blood Pact prevented it. Fans have known for a while that the Fantastic Beasts series is building up to the legendary duel between Grindelwald and Dumbledore, but now we are really starting to see these two great wizards come to the forefront.

Related: Fantastic Beasts 2's Dumbledore Twist Is A Dangerous Retcon (But Also Brilliant)

We're also discovering some new lore about their magical battle, including the fact that Dumbledore and Grindelwald made a Blood Pact when they were young... and this pact has to be broken before Dumbledore can take him down. But the big question here is: can Dumbledore even break the Blood Pact? And if so, then how?

The Blood Pact In Fantastic Beasts 2

Dumbledore's role in Fantastic Beasts: The Crimes of Grindelwald isn't as large as that of Grindelwald himself, but he does have a few very important scenes where we learn a little more about his history with the Dark Wizard (and his time as a teacher at Hogwarts). Throughout Fantastic Beasts 2, we see Dumbledore being approached by the Ministry of Magic, and asked to take the fight to Grindelwald, which he refuses... every time. He simply shakes his head sadly and says he can't, thus leading fans to believe that he simply still cares too much for Grindelwald to be able to fight him. Obviously, the Ministry is led to believe the same, which causes them to become very suspicious of Dumbledore, believing that he may still be sympathetic to Grindelwald's cause.

Related: Harry Potter Theory: Dumbledore Was Lying About Grindelwald All Along

However, we learn toward the end of Fantastic Beasts 2 that Dumbledore's reticence isn't about his love for Grindelwald, but about a literal inability to "move against him" thanks to a Blood Pact that the two of them made when they were close to each other. We see him, looking into the Mirror of Erised, where he sees the two of them cutting their palms with wands and clasping hands, as a drop of their co-mingled blood is magically enclosed in a vial. This, like an Unbreakable Vow, is a spell that cannot be undone or gone against, which is why Dumbledore has Newt working for him, and Grindelwald has recruited Credence for his own side.

Dumbledore Can't Break The Blood Pact (Yet)

We know that, eventually, the Blood Pact between Dumbledore and Grindelwald is broken - because they have their legendary duel in 1945. However, in 1927, Dumbledore is unable to get around the vow he made as a youth to never fight the boy he loved. However, Dumbledore is one step closer to breaking the pact, because Newt used a Niffler to steal the magical vial from Grindelwald, who used to keep it on his person at all times. So now Dumbledore has the vial, and he can get to work on breaking it - although, given the dates of the film and his duel, it's going to take him some  time.

We don't know a whole lot about Blood Pacts so far, because this is brand new lore J.K. Rowling has created for the Fantastic Beasts franchise, but we can make some educated guesses. In many ways, this spell appears to be similar to an Unbreakable Vow - with a few tweaks. For one thing, the Blood Pact can be made without a Bonder (a person to build and set the spell), whereas when Narcissa and Snape made the Unbreakable Vow in the Harry Potter series, Bellatrix had to act as Bonder for them.

Related: Harry Potter/Fantastic Beasts Official Timeline

For another, breaking the Unbreakable Vow simply ends in death, whereas it would seem that if a wizard can break the vial of the Blood Pact, the pact itself will be broken. We don't know if there will be any repercussions to breaking the pact, though - all we can surmise from Fantastic Beasts 2 is that the pact makes it physically impossible for either wizard to move against the other, and that the vial is the key to the pact. However, this is powerful magic, and at the time of Fantastic Beasts: The Crimes Of Grindelwald, Dumbledore doesn't know if it will even be possible to break it.

Page 2 of 2: How Dumbledore Can Break The Blood Pact

Dumbledore Breaks The Blood Pact With Dragon's Blood

Dumbledore has done plenty of amazing things in his career as a wizard, but only three major accomplishments are listed on his chocolate frog card: "His defeat of the Dark Wizard Grindelwald in 1945, for the discovery of the twelve uses of dragon’s blood, and his work on alchemy with his partner, Nicolas Flamel." Two of these three have already appeared in the Fantastic Beasts franchise (or will appear, in the case of the duel), so it's very possible that the third will also be a part of the series as Dumbledore discovers that one of the uses of Dragon's Blood is to break a Blood Pact.

Although his discovery of the Twelve Uses of Dragon Blood was major, and is also mentioned in his obituary and the book that Rita Skeeter wrote about him after his death, not many of the twelve uses have actually been confirmed. Rowling has previously mentioned that one of the uses is as oven cleaner, and another is spot remover; extremely prosaic uses, really. It's not likely that Dumbledore would have become famous for discovering the Twelve Uses of Dragon Blood if they're primarily used to help people clean, though, so we have to assume that some of the remaining ten uses are a whole lot more impressive.

Related: Fantastic Beasts 2 IMPROVED Harry Potter Canon

We also don't know exactly when this discovery was made - it's never dated in the Harry Potter books, which gives Rowling quite a bit of leeway when crafting the rest of the Fantastic Beasts story. So there is no reason that Dumbledore couldn't start working with Dragon's Blood as a way to break the curse. This would also tie into the Fantastic Beasts element of the franchise, as Newt would (presumably) be the one recruited to get hold of Dragon's Blood for experimentation. Finally, it has a nice symmetry - blood to break blood.

What This Means For Fantastic Beasts 3 (& Nicolas Flamel)

Fantastic Beasts and Where to Find Them was all about setting up a new corner of the Wizarding World, creating the lore of magic in America, and introducing the new characters that fans would grow to love. Fantastic Beasts: The Crimes of Grindelwald is all about setting up Grindelwald's evil plans and a few big questions for the audience (and setting fans on the path to that legendary duel). Now Fantastic Beasts 3 is supposed to be giving fans some answers, presumably to the Credence/Dumbledore mystery, but also possibly for Dumbledore, Grindelwald, and the Blood Pact.

Related: What Fantastic Beasts 3 Needs To Do To Save The Harry Potter Prequel Series

We are sure to find out a whole lot more of Dumbledore's history and his time with Grindelwald (and, hopefully, a little less pussyfooting around the romantic aspects of their relationship) - and more about the Blood Pact as well. While the core conflict of Fantastic Beasts 3 isn't yet known, it's not likely to be the duel itself, given that there are supposed to be five movies in the franchise, but we'll definitely keep building in some backstory and moving toward that final fight. Which means we'll be spending more time on the Blood Pact and Dumbledore's attempts to break it - and possibly, his discovery of a few more uses of Dragon's Blood along the way. We may well see Nicholas Flamel again, too, as Dumbledore continues to work with him on the Blood Pact and the way that Dragon's Blood could help to break it. There's another character that may pop up as well; Ivor Dillonsby, who told Rita Skeeter that he had already discovered eight uses for Dragon's Blood when Dumbledore borrowed his notes.

Of course, there may be other ways to get around this Blood Pact that haven't yet come to light, especially as we know so little about this kind of magic. Assuming that the pact was made before Ariana's death, it does seem as though there is at least one loophole - as Albus, Aberforth, and Grindelwald all fought each other on that fateful day. Perhaps Dumbledore can exploit this loophole again (is it breakable to save a family member's life? Could Credence be the family member that Dumbledore tries to save?). Perhaps something else will pop out of Newt Scamander's suitcase to help or that Dumbledore will be able to figure it out in some other way. Only time will tell, but this is sure to be a significant part of Fantastic Beasts 3 and onward.

More: Fantastic Beasts 3: Release Date, Story Details & Every Update