It's not the Brass God that wrecks everything so much as it is all the plane(t)s and timelines that orbit it, singing world-refusals. The Surrender of Alinor happened in one hour, but Numidium's siege lasted from the Mythic Era until long into the Fifth. Some Mirror Logicians of the Altmer fight it still in chrysalis shells that phase in and out of Tamrielic Prime, and their brethren know nothing of their purpose unless they stare too long and break their own possipoints.