10 Harry Potter Mysteries JK Rowling Has Actually Answered
4. Why Didn't Harry Develop An Obscurus?
As soon as Fantastic Beasts And Where To Find Them hit cinemas, the Internet came alive with the question, "So why didn't Harry Potter have an Obscurus bursting out of him and wrecking the place?" He, especially when locked under the Dursley's stairs, seemed like a mirror image of the repressed and barely controlled Credence. Surely his magic would be ready to burst out like a fit of rage too?
Alas, no. Credence Barebone knew he was magical and was taught that it was evil and dangerous, so he fought day and night to keep it in. Harry Potter was saved this difficulty by one simple thing: he just wasn't aware of his magic. He knew of nothing to hide and therefore repressed nothing.
In fact, as we see in the early pages of the first book, he does let his magic out on occasion, regrowing his hair overnight, leaping onto the roof of his primary school to avoid a gang of bullies and shrinking an awful outfit to avoid wearing it.
According to JK Rowling's new website: "Even when he was scolded for ‘making things happen’, he didn’t make any attempt to suppress his true nature, nor did he ever imagine that he had the power to do so."