Warning! Spoilers for Justice League #55 below!
In DC's Dark Multiverse the Justice League are using what little strength they have left to save J'onn J'onzz as well as the Legion of Doom from the tyrannical and original creator of the multiverse - Perpetua. But while attempting to rescue their lovers and friends, they come face to face with one of the most powerful dark knight's they've ever seen... the Omega Knight.
Quite possibly one of the most sinister villains the DC Universe has ever seen is Perpetua - a creator who seeks to rule and contort the multiverse with the help of The Batman Who Laughs through a means of building an army of evil Batmen to infect each universe with madness. After The Batman Who Laughs forms an alliance with Barbatos - a being bent on devouring universes they are able to rapidly gather the Dark Multiverse's most malicious Batmen who eventually become known as the Dark Knights. Due to Perpetua and The Batman Who Laugh's immense reach into the multiverse, the Justice League have faced multiple Dark Knights before. But nothing can prepare them for the Omega Knight, which is a being brewed from the severed bodies of the Omega Titans - a group of creators who may have brought life into the universe at its beginning.
In Joshua Williamson, Robson Rocha, Daniel Henriques, Liam Sharp, and Simone Bianchi's Justice League #55 the Justice League have a run-in with the villain known as Starro - a starfish-shaped alien who seeks to control all of humanity. After battling Starro, they escape on a ship that Lex Luthor calls Lana and head to Perpetua's domain and the Brimstone Bay to rescue J'onn as well as the Legion of Doom. As the Justice League inch closer to Perpetua's throne, Hawkgirl senses that her lover J'onn is close by and he needs her help. After Lex tells her not to run off in search of J'onn, she punches him in the face and runs off anyways.
As Hawkgirl searches and eventually discovers her lover, the rest of the Justice League uses stealth tactics in an effort to sneak into Perpetua's lair and find the Legion of Doom. But what the Justice League doesn't know is that their location has already been given away because one of the Dark Knights is using J'onn to lure Hawkgirl as well as the Justice League to Perpetua's throne and Brimstone Bay. Not only does the Dark Knight lure Hawkgirl and the Justice League, but he also lets the Omega Knight - Perpetua's leading protector know of their whereabouts. Soon, the Omega Knight stands before the Justice League with it's Kaiju-like body and vaporizes them with a purple beam of light.
Although it appears that the Justice League team are killed by the Omega Knight at the end of the comic, nothing is certain. But if the Justice League have any hopes in defeating the darkness that is spreading throughout multiverse as well as stopping Perpetua and The Batman Who Laughs, they will need all the help they can muster.