There are countless theories offering answers to the many mysteries of Harry Potter universe, but the new Fantastic Beasts And Where To Find Them movie may have just shed light on the biggest one: Ariana Dumbledore. If you haven't seent eh film this will contain spoilers so read at your own risk!
So how does the new movie link to the sad fate of Dumbledore's family? Well thanks to the new flick we know about Obscurial’s. If you can't quite remember it's "a young wizard or witch who developed a dark, parasitical magical force, known as an Obscurus, as a result of their magic being suppressed through psychological or physical means due to their fear of being persecuted by Muggles." (Thanks Harry Potter Wikia!)
Poor Ariana, as we learn in the Harry Potter series, was never the same after she was terrorised about her magic by young muggle boys when she was six. We also learn from her brother Aberforth that she was VERY unstable...
"It destroyed her, what they did: she was never right again. She wouldn’t use magic, but she couldn’t get rid of it; it turned her inward and drove her mad, it exploded out of her when she couldn’t control it, and at times she was strange and dangerous. But mostly she was sweet and scared and harmless"
Hmmm sounds like an Obscurus doesn't it? We also know that the only way for an Obscurus to die is if the witch or wizard it lives in dies... and Ariana died. IT'S ALL MAKING SENSE NOW!!!
In Fantastic Beasts they say that they're rare and the only two cases in the last 200 years have been young Sudanese girl and Credence. But now we're not so sure... We know Grindelwald was present when Ariana died at 14, and we know his search for power really took off after that... maybe this triggered the whole thing and that's just one more reason Albus feels responsible?
Ariana has always been one of the saddest stories within the Harry Potter realm for us. Her fate is so unfair so we really hope JK Rowling explores this in the next movies and gives us more info!