Fight takes place on an indestructible, endless flat arena. Shared universe rules apply, so "The Force wouldn't work on Miraak" or "Miraak has no Force resistance" doesn't apply. We will assume that magic/energy from both universes interact under the same umbrella.
Who takes it?
__________________ “There are aspects of who we are that can only be revealed to us in the deepest pit of intolerable suffering, in those moments when all else is torn away—when we stand at the very brink of eternity itself and stare death in the face.” —Darth Sidious