J.K. Rowling said: 'Dumbledore fell in love with Grindelwald, and that added to his horror when Grindelwald showed himself to be what he was…
"I always saw Dumbledore as gay," Rowling said in response to a fan question about Dumbledore's love life. "Dumbledore fell in love with Grindelwald" and was "blinded" by it. "This was Dumbledore's tragedy."
While it is confirmed that Dumbledore was in love with Grindelwald, and the pair shared an intimate relationship as lovers during their time together, they did not enter into an exclusive relationship.
While their romantic relationship doesn't progress farther than those pained one-liners in the movie — they don't kiss, but they're far from together in this film — the extra layer of shared history, and nuance, makes the relationship between the two men that much more compelling.
Warner Bros. Dumbledore and Grindelwald only spent about two months together, but the two canonically became lovers in that time. Their relationship was passionate and intense, and each wizard helped shape the philosophies of the other.
And one theory that has emerged is Credence, or Aurelius, is actually Dumbledore's son rather than his brother.
Believing they were working towards the greater good, Dumbledore and Grindelwald parted ways following the death of Albus' sister Ariana who was caught in the crossfire of a duel between Dumbledore, Grindelwald, and Albus' brother Aberforth.
In the opening scene of The Secrets of Dumbledore, Albus Dumbledore (Jude Law) revealed that he was in fact in love with Gellert Grindelwald (Mads Mikkelsen) when they were teenagers, and the blood oath was a witness of their love.
Dumbledore and Grindelwald took a blood oath to not fight each other. "Fantastic Beasts: The Crimes of Grindelwald," the second film in the series, reveals that as teenagers Dumbledore and Grindelwald undertook a blood pact that wouldn't allow them to move against each other.
It turns out that Credence isn't Albus' brother — he's his nephew. "The Secrets of Dumbledore" circumvents the timeline issues by revealing that Credence — or rather, Aurelius — isn't Albus' brother. He's Aberforth's son, which makes him Albus' nephew.
Credence Isn't Voldemort's Dad But He Could Be Snape's Grandpa. Before Fantastic Beasts and Where to Find Them came out, it seemed like the story's only real Potter connection would be Newt Scamander's relation to Luna Lovegood and a Dumbledore name-drop.
Translation for the non-Harry Potter set: Dumbledore and Grindelwald are both wizards introduced in the original Rowling books; Rowling revealed after publishing her series that Dumbledore was gay, and very much in love with Grindelwald.
Aberforth Dumbledore
Aberforth is the younger brother of Albus Dumbledore and owner of The Hog's Head Inn in Hogsmeade. He clearly has quite a lot of resentment towards his brother, as well as Grindelwald, which is mainly due to the death of his and Albus' little sister, Ariana.
Behind the scenes
Vinda Rosier is portrayed by Poppy Corby-Tuech in the second and third instalments of the Fantastic Beasts film series. Her name is given only as "Rosier (female)" in Fantastic Beasts: The Crimes of Grindelwald - The Original Screenplay, but her first name was revealed on Pottermore.
He even apologizes for keeping his distance from Harry during the year. He feared his love for Harry would make Harry vulnerable to possession by Voldemort. Dumbledore reveals how thoroughly he loves Harry.
Albus was fascinated by Grindelwald's research on the Deathly Hallows and ideas of wizarding domination, and their friendship soon turned into a romantic relationship, in which Albus fell in love with Grindelwald.
Ariana Dumbledore was the sister of Albus and Aberforth Dumbledore. She died quite young, at approximately 14 years of age.
The Secrets of Dumbledore is the first official movie in the Harry Potter franchise to openly reference his sexuality, but it's limited to a select few scenes.
One particularly popular theory is that Credence is really Tom Riddle Sr., Voldemort's father. However, given Voldemort's British origins, Tom Riddle's Muggle status, as well as the timeline of his birth — in December of 1926 — it seems extremely unlikely that Credence is actually Tom Riddle Sr.
It is explained that Credence is the illegitimate son of Albus's younger brother, Aberforth (Richard Coyle). His real name is Aurelius Dumbledore.
It's stated that Credence was born in 1901. That would tie in with Leta Lestrange being around the age of 6 or 7 when she swapped the babies and made him about 26 years old during the events of Fantastic Beasts: The Crimes of Grindelwald.
Fantastic Beasts: The Secrets of Dumbledore confirmed that Credence Barebone/Aurelius Dumbledore (Ezra Miller) is the new Snape (Alan Rickman) through a very familiar line delivered by Aberforth Dumbledore (Richard Coyle). Fantastic Beasts 3 finally shed light on the Credence being Aurelius Dumbledore plot twist.
Credence Barebone (born Aurelius Dumbledore, c. spring 1900) was an English-born American half-blood wizard who lived during the 20th century. He was the son of Aberforth Dumbledore and an unnamed woman. One year after his birth, he unexpectedly was taken to America with his Aunt.
So the suggestion is that Credence Barebone and Nagini will turn out to be Snape's grandparents. This is certainly not the first time that Nagini has been theorized to be related to someone in Harry Potter, and it is definitely not the first time it has been suggested that Credence and Nagini will become an item.