“The truth is that Credence is magical and he’s been repressing his magic. The forces of the universe come into a physical form, which is an Obscurus, and that Obscurus initially comes to an Obscurial as a friend, encouraging them, then with increasing severity to…

“The Obscurus is a really wonderful idea that Jo came up with. When a child is prohibited from developing their magic in a healthy, normal, organic, regular way, this dark energy can develop, and can suddenly get out of control, wreaking havoc and being quite…