The American wizard Percival Graves never existed, and this key detail puts the events of Fantastic Beasts and Where to Find Them in a whole new light.
When Fantastic Beasts revealed that Colin Farrell’s Percival Graves was really the dark wizard Gellert Grindelwald in disguise, the natural assumption was that he was using Polyjuice Potion to assume a real Auror’s identity. After all, J.K. Rowling had set a precedent with Harry Potter and the Goblet of Fire, when Barty Crouch Jr. used Polyjuice to pose as Mad-Eye Moody. But Rowling recently set up a new website separate from Pottermore, where she revealed something surprising: Grindelwald did not use Polyjuice Potion.
In a Fantastic Beasts questions and answer section on her site, Rowling writes,
Q: Why did ‘revelio’ undo the effects of Polyjuice Potion?
A: It didn’t. Grindelwald’s Transfiguration surpasses that of most wizards, so he used a spell, not a potion, to take on the appearance of Percival Graves.
On the one hand, this makes the plot of Fantastic Beasts make less sense. If Percival Graves was not a previously established identity, then how was Grindelwald able to rise through the MACUSA ranks in such a short amount of time? Shouldn’t they have better security measures in place regarding Wizards who can get close to the President?
But on the other hand, there is a precedent in the Harry Potter world for disguise through Transfiguration. Recall Harry Potter and the Deathly Hallows. When the trio breaks into Gringotts, Hermione takes Polyjuice to pose as Bellatrix Lestrange, but Ron simply transfigures his facial features and pretends to be a random foreign wizard.
From Deathly Hallows:
Hermione sighed and set to work, muttering under her breath as she transformed various aspects of Ron’s appearance. He was to be given a completely fake identity, and they were trusting to the malevolent aura cast by Bellatrix to protect him. Meanwhile Harry and Griphook were to be concealed under the Invisibility Cloak…It was just not possible to discern Ron under his disguise, but only, Harry thought because he knew him so well. Ron’s hair was now long and wavy; he had a thick brown beard and mustache, no freckles, a short, broad nose, and heavy eyebrows.
“Well, he’s not my type, but he’ll do,” said Harry.
The movie did a shoddier job with Ron’s “disguise,” but the implication is still there.
It’s yet another subtle connection between Fantastic Beasts and Harry Potter.