“The idea of beasts works on several different levels within the movies. There’s the literal sense of non-human creatures: some of them cute, some of them terrifying, some simply strange. Then there is the metaphorical sense of the beast inside a man, the crude emotions that a manipulative genius like Grindelwald knows how to stoke and use. We’re also dealing with the idea of beastly people: that some humans are something less than human. Even where there is great charisma and intelligence, there may be an utter lack of conscience. Finally, I’m exploring the idea of creating beasts, which is to say, othering or dehumanising our fellow people, as the first step towards cruelty or extermination.
So through this beastly landscape walk our original four characters, led by the shambling figure of Newt Scamander, who loves the purity of creatures that the world might call monsters. The human world around Newt and his friends is becoming darker and more complex, and the original hunt for escaped creatures will become a hunt for something much more elusive and difficult: a return to humanity.”
Source: JK Rowling’s Official Website