Today saw the release of Batman: The Devastator #1, the Bruce Wayne of Earth -1 detailed his origin story, explaining how it was an evil Superman that led him to become an evil Doomsday Batman.
As in The New 52, there was a "Doomsday virus," something with which one could infect oneself to gain Doomsday-like powers and appearance.
On Earth -1, this Dark Multiverse's Batman was friends and teammates with Superman, although he never fully trusted the Man of Steel. In a comic seemingly inspired by the DC Extended Universe, Batman continued to be paranoid that Superman would try and kill him.
In the story, we saw Superman designing a weapon to help in case it ever happened.
Eventually, Superman DID snap on this Earth, killing his wife and going on a murder spree. In another nod to the movies (it seems), Batman attacks Superman with a Kryptonite spear...
...but that ws a fake-out, and what the real weapon was, was an enhanced Doomsday virus, which powered up Bruce in a manner that he could use to kill Superman.
Shortly thereafter, the Devastator was recruited by the Batman Who Laughs, who told him of another world, a world where Superman had not yet killed, and where his friends could still be saved.
Is this the most "salvageable" of the Dark Knights? In some ways it feels like it, although one has to wonder whether that is really the story Snyder and Capullo are telling here.
You can get Batman: The Devastator at your local comic shop, or buy a digital copy here.