Question: are dumbledore and grindelwald related?
Answer: Once there, Grindelwald reveals Credence's true identity to him: He is Aurelius Dumbledore, Albus Dumbledore's brother. ... Based on the way Aberforth describes what happened to Ariana, some fans have concluded that she was also an Obscurial after witnessing Credence's powers in the first Fantastic Beasts.