Question: what relation is credence to albus dumbledore?
Answer: Once there, Grindelwald reveals Credence's true identity to him: He is Aurelius Dumbledore, Albus Dumbledore's brother. Now, here's where things get a bit tricky. As we know from the Harry Potter series, Dumbledore had two younger siblings who were known to the public, his brother Aberforth and sister Ariana.