WARNING: The following contains spoilers for Dark Nights: Death Metal #3, by Scott Snyder, Greg Capullo, Jonathan Glapion, FCO Plascencia and Tom Napolitano, available now.
The original Dark Nights: Metal event series introduced the first evil Dark Knights that hailed from the Dark Multiverse. Each of them were alternate versions of Batman that represented a different member of the Justice League: the Merciless was a Batman with the powers of the God of War; the Red Death was a Bruce Wayne with Barry Allen's super-speed; and the Murder Machine was a cross between the Dark Knight and Cyborg. And of course, all of these characters were assembled into one fearsome team by the Batman Who Laughs, a version of Batman who'd been infected by the Joker's madness.
The sequel series Death Metal took that concept even further by introducing even more alternate versions of Batman. The first few issues of the series introduced the Batmage, the Beyonder, B-Rex, Batom, the Robin King, the Batmanhattan and even a Judge Dredd Batman. And now, in Dark Nights: Death Metal #3, two more new evil Batmen join the ranks of the Dark Knights.
At the end of Death Metal #2, Wonder Woman and her allies unleashed a new weapon to help in their fight against the Batman Who Laughs and his enforcers: a giant mech composite of Superman, Batman and Wonder Woman. Now, as we learn in Death Metal #3, the giant robot is piloted by Jonah Hex, and it's being used as a diversion so the Amazon Princess and her allies can infiltrate Megapokolips.
As the issue begins, the robot has already been shot down by three Dark Knights -- one of whom is a Batman/Silver Surfer composite called Night Glider. The other two merge Batman with two powerful DC supervillains.
The first is called the Collector, and he is a mix of Batman and Brainiac. Brainiac is a powerful alien who has been a longtime enemy of Superman and the Justice League since he debuted in a story by Otto Binder and Al Plastino in Action Comics #242. He flies a giant skull-shaped ship, and he goes through the cosmos collecting cities from different alien civilizations that he miniaturizes to keep aboard his ship. This is likely why the Batman version of Brainiac is called the Collector, and he seems to do the same, wearing armor inspired by Brainaic's technology.
The other Dark Knight is a composite of Batman and Atrocitus. Atrocitus is a Red Lantern, a dangerous enemy of the Green Lantern Corps who debuted in Geoff Johns and Ethan Van Sciver's Green Lantern #25. As an alien who once lost everything because of the Guardians of the Universe, Atrocitus is fueled by anger, and his rage has no equal. In Death Metal, the cross between Batman and the Red Lantern is appropriately called Batrocitus. His costume clearly shows that he is a member of the Red Lantern Corps, and it gives the character a new logo that mixes the Bat-symbol with the Red Lanterns' logo.
Batrocitus and the Collector make for two interesting new additions to the Dark Knights because they mix Batman with iconic villains. Unfortunately, they don't appear in Death Metal #3 for very long.
After shooting down the Wonder Woman/Batman/Superman composite mech, Night Glider, Batrocitus and the Collector all find Jonah Hex inside. The cowboy realizes what he must do to finish his mission: engage the robot's self-destruct sequence. The three Dark Knights don't have time to escape and all three are seemingly killed by the explosion, dying as quickly and brutally as many of the Dark Multiverse's other Batmen did.