WARNING: The following contains spoilers for Justice League #8 from Scott Snyder, James Tynion IV, Jim Cheung, Stephen Segovia, Mark Morales, Tomeu Morey, Wil Quintana and Tom Napolitano, on sale now.
As grand and large as the DC Universe is, it's safe to say almost everything revolves around Earth. Sure, there are adventures in space with the Green Lanterns, alternate reality stories and a plethora of tales that span the entire multiverse, but we can agree our planet is of central importance.
As the origin place of many heroes and villains, Earth has had crisis after crisis. Now, another planet has gotten fed up with Earth, viewing it as the bane of the multiverse's existence. That planet is Thanagar Prime, which has been stockpiling an arsenal with which to wipe out Earth.
In Justice League #15, Martian Manhunter, Hawkgirl (Kendra Saunders) and the Green Lantern (John Stewart) seek the Martian Keep to find out what secrets Thanagar Prime is hiding in its vaults. They use J'onn's mental abilities to disguise themselves and infiltrate its catacombs, fooling the guards and Dominators into thinking they're with the Thanagarian army. As they get closer to the Keep's prison, John reveals the ruse, and all hell breaks loose. This leads to the startling revelation that Earth is the target of an alliance to take the planet out.
One of the Dominators spills the news in battle, revealing Earth is a blight that only causes chaos and destruction. It seems that after the Source Wall was broken and its energy spilled out into the DC Universe, many entities blamed the League, deciding that act was the last straw. The Dominators reveal they're planning to destroy Earth before it kills everyone else, with the likes of the Guardians of Oa apparently also in on the plan.
Kilowog and the Guardians come to arrest J'onn, which is suspicious since the Guardians don't have jurisdiction on Thanagar Prime. Even if the group is not directly involved in an impending genocide, the fact it leaves Thanagar Prime to its own devices makes the Guardians an indirect accomplice, leaving readers to wonder who else is involved in this galactic cabal.
Thanagar Prime itself is a warlike world unlike any other and, as the League finds out, its resurrection isn't even real. It's a mental projection thanks to the Absorbascon, which makes memories real. The Absorbascon is also how Shyera Hol (Thanagar Prime's Empress and the previous Hawkgirl) revived her homeworld and her people, including the Savage Hawkman. It's a facade, but a deadly one.
What's interesting is that this alliance now has a very good reason to destroy the Earth, as the planet houses the Totality. Perpetua, the creator of the previous DC multiverse, is trapped in the Totality, so eliminating the planet and everything on it will preserve the fabric of the current reality. Survival is the ultimate goal of planets like this, after all.
But the coalition could have ulterior motives as well, as the Dominators indicate they would love to harvest Earth for its metahuman gene for the purposes of trafficking and weaponization. Either way, this is a big development, because if Thanagar Prime brings war to Earth's doorsteps, it has the firepower to defeat the League. With the backing of other alien armies, Thanagar Prime might just be ready to put an end to Earth once and for all.