WARNING: The following contains spoilers for Batman/Superman: Authority Special #1, on sale now from DC Comics.
The importance of the DC Multiverse has been especially apparent in recent years, with many of the threats that have confronted the main DC Universe coming from beyond, and rewriting reality over the course of epic conflicts. While the heroes triumphantly restored the multiverse during the events of Dark Nights: Death Metal, the cosmic threats continue to plot their next moves from the hidden spaces between universes. As Batman teams up with the Authority, the fate of one cosmic god that navigated the multiverse as a de facto caretaker is revealed, with the tragic return of Tempus Fuginaut.
Introduced in 2018's Sideways #1, Tempus Fuginaut is member of a race of omnipotent beings -- the Fuginauts -- tasked with preventing intrusions between universes; Tempus was tasked specifically with ensuring the Dark Multiverse did not invade the prime DC Universe. After teaming up with Wally West during the comic book miniseries Flash Forward to prevent further Dark Multiverse incursions in the lead-up to Death Metal, Tempus' sad fate is revealed in Batman/Superman: Authority Special #1, by Phillip Kennedy Johnson, Trevor Hairsine, Ben Templesmith, Jonathan Glapion, Scott Hanna, Rain Beredo and Tom Napolitano.
In the wake of Death Metal, and the defeat of the Batman Who Laughs, the Empire of Shadows has risen as the new force to be reckoned with in the Dark Multiverse. Carrying on the fearsome legacy of Ra's al Ghul, the regime has conquered its universe and now sets its sights on others. To that end, the Empire of Shadows discovered Tempus in the space between worlds and reduced him to a ruined husk, using his butchered remains as a device to travel to other universes.
Upon learning of the threat posed to the DCU by the Empire of Shadows, Batman teams with Superman and the Authority for a preemptive strike. It's a daring mission into the heart of the Dark Multiverse to seize the remains of Tempus Fuginaut and return home, effectively leaving the Empire of Shadows confined to its own world.
In the aftermath, with Batman and the Authority safely back on their own world, the Empire of Shadows decides not to continue its quest for multiversal domination through the use of Fuginauts. Instead, the Empire's head vows to proceed undeterred, with a rematch against the Authority in the cards as he and his children look into other ways to conquer alternate universes.
While Batman and the Authority may have dealt the Empire of Shadows a major setback and discovered the tragic fate of Tempus Fuginaut, the superheroes seem to have only delayed an inevitable showdown against new villains from the Dark Multiverse.