Dont be a fool
So, the Angels we know from planes such as Innistrad , Kaladesh , Dominaria, and Ravnica are all celestial beings guided by the whims and prejudices of white mana
If you kept one Hawk in hand, and then recast it, you would get two more Hawks, and thus one Hawk and Jace would give you a net of SIX total cards
You'll find the full developer post over at the official website, but if you're looking for the short version, here's a couple of choice quotes: "To affirm what we talked about back in September, a smarter system that provides what we have dubbed "duplicate protection" is still our top contender, and the current design space we're working with." "Okay, so we have the goals we want to accomplish, we have the problem space, and we have a system that will help us reach these goals
Are you sacrificing a creature to it like Carnage Altar