There is a bunch of clues given by the showrunners in this interview. I'm outlining the important ones below:
Our sympathies are so aligned with the hosts it’s easy to think of the Man in Black as absolute black evil with a wry smile....So that’s what we’re approaching here, is a shift in perspective that might allow us to imagine a different side of his character that he shows the outside world"
"Here, we’re reminded that you underestimate this guy at your peril. He has his own designs of what he wants this place to be. You’re also reminded he has an extremely controlling relationship with the hosts. Like the moment when he cuts a host’s face open and you realize why they’re all stripped bare in cold storage, that it’s a very practical measure on his part to make sure nobody makes Arnold’s mistake again, that treating these hosts as machines is vital to ensure that the techs who work with them don’t mistake them for people. You’re reminded that Ford is not a friend to the hosts. He’s a father figure and that can go a number of different ways. "