… necessarily produces empathy and identification. A story requires us to understand a protagonist’s motivation - and understanding requires some degree of identification. In effect the whole power of story-telling comes from its ability to allow us to imagine ourselves in someone else’s shoes.

Surely what Blake understood was that Milton didn’t consciously choose to make Satan his hero. Putting Satan at the centre of the story required Milton to make him the hero, whether he wanted to or not. Sympathy with the devil was implicit from the inception.