WARNING: This article following contains spoilers for Justice League/Aquaman: Drowned Earth #1 by James Tynion IV, Howard Porter, HI-FI and Tom Napolitano.
Scott Snyder and James Tynion IV’s Justice League run thus far has seen the world’s greatest heroes tackle threat after threat with no time to really slow down. With Batman in a full body cast and the cosmic trio of Hawkgirl, Martian Manhunter and Green Lantern John Stewart stuck in the middle of space, things can’t possibly get any worse.
Except it can, as Justice League/Aquaman: Drowned Earth #1 shows us.
As the title implies, Aquaman is at the forefront of this story, having been captured by an ancient race of aquatic beings known as the Ocean Lords. The Lords previously tried to take over the Earth, but Poseidon defeated them forever ago and banished them to the dimension known as the Blood Reef.
Separated from Wonder Woman and Firestorm while searching for the sea god's supposed gift (only to come face to face with a space Kraken), Arthur is helpless as the rest of the world is submerged in water that turns anyone into monsters upon physical contact. Even Atlantis, a place that consists primarily of water, is subject to this, though Mera and Ocean Master are immune to the transformation and have to hold the line alone.
When Aquaman won’t capitulate to the Ocean Lords' demands to wield the power of the ocean with true force, the Lords turn to someone else to wield the power instead: Black Manta.
Manta has always had an axe to grind with the King of the Sea, but often comes up short because he's just a human with a fish bowl on his head. When he isn't trying to destroy Atlantis, though, he does try to take relics from ancient undersea civilizations, something we saw previously when his son became the new Aqualad.
That went poorly, and the undersea villain has since joined up with the Legion of Doom, though not given the chance to fight his nemesis. Teaming up with the Lords is another part of the Legion's agenda, it just also has the extra benefit of giving Manta a new arsenal.
As Ocean Master succumbs to his beastly transformation and the Justice League gets assaulted by various Ocean Lords, Aquaman gets the Heart of the Ocean stolen from him and put into the body of his sworn enemy. Sadly, it’s not shown what he can do with the power just granted to him, but he does take the opportunity to roast Aquaman about using the power to primarily talk to fish.
What Black Manta does next with this power remains to be seen, of course, but it surely won't be good. The sea is a powerful thing, and in the hands of a madman it'll be downright terrifying.