Warning: The following article contains spoilers for The Green Lantern #9, by Grant Morrison, Liam Sharp, Steve Oliff and Tom Orzechowski, on sale now.
The heroes of the DC Universe love helping themselves. Since the Barry Allen Flash of Earth-1 met Jay Garrick's Flash of Earth-2 in the 1960s, DC's heroes have teamed up with other versions of themselves from around the multiverse on a regular basis.
While the Supermen of the Multiverse teamed up to help solve Final Crisis, Batman teamed up with some of his alternate reality counterparts to take on the Batmen of the Dark Multiverse in Dark Nights: Metal. In both comics and on TV, the Flash still seeks the advice of his counterparts from other worlds on occasion.
While Hal Jordan and the other members of the Green Lantern Corps are tasked with protecting the universe, they've had fairly limited interactions with their multiversal counterparts. However, that changes in The Green Lantern #9.
When a planet-destroying Mad Lantern breaks into the DC Universe in search of Hal Jordan, the Green Lantern is rescued by some of the Guardians of the Multiverse, a group of Green Lanterns from alternate realities.
While the Mad Lantern slaughters a team consisting of the Superman foe Vartox and several unfamiliar heroes in a distant universe, Hal Jordan was trying to take some time off on the planet Athmoora. However, Hal and some of his alien friends found themselves fighting the green dragons of the space wizard Ah-Bah-Nazurr.
Over the course of the fight, Hal Jordan realizes that Ah-Bah-Nazurr is a version of Abin Sur, the Green Lantern who first gave him a power ring. Freed from the talisman that drove him mad, Abin Sur explained that he was from Earth-20, a world full of pulp fiction-inspired heroes that was featured in Morrison and Chris Sprouse's The Multiversity: Society of Super-Heroes #1.
While Abin Sur describes the Mad Lantern, the "dread emissary of the Reverso-verse" breaks into the DC Universe, looking for the DC Universe's main Green Lantern. In the midst of Abin's battle with the creature, three more Green Lanterns show up to rescue Hal, introduce themselves as the Guardians of the Multiverse and take him to parts unknown.
Like Abin-Sur and Earth-20, all of these Green Lanterns have made minor appearances around the DC Multiverse before. The Batman Green Lantern was introduced in 1994's Batman: In Darkest Knight, which was set in a world where Bruce Wayne received a Green Lantern ring instead of Hal Jordan. In the current DC Multiverse, that world, Earth-32, is home to amalgamated versions of several DC heroes.
The torch-wielding Green Lantern next to him is Flashlight, a member of the Justice 9. His world, Earth-36, was created by Morrison and Ivan Reis in 2015's The Multiversity #1, and is inspired the world of Big Bang Comics, which features a pastiche of Golden and Silver Age DC heroes.
The final Green Lantern featured here is the Magic Lantern, who was created by Morrison and Charles Truog in 1990's Animal Man #23. In a world inspired by '60s counterculture, the Magic Lantern protects Earth-47 along with the teenage president Prez and Brother Power the Geek as a member of the Love Syndicate of Dreamworld.
Although these Guardians of the Multiverse rescued Hal Jordan, it's not entirely clear why the Mad Lantern wants him. The creature's glowing green fist and its name suggest that he has some kind of connection to the Green Lanterns, but it's simply an engine of destruction for the moment. According to the solicitation for the next issue, Hal and a few mroe Guardians will team up to take on the Mad Lantern.
In a larger cosmic sense, the introduction of the Guardians of the Multiverse could have massive ramifications on the DCU's cosmic order. If the Green Lantern Corps has a multiversal equivalent, it's not hard to imagine similar multiversal organizations existing for DC's other Corps like the Red Lanterns and the Star Sapphires.
Even though the full might of the Green Lantern Corps and its allies on the emotional spectrum give Hal Jordan a legion of allies, the mere existence of the Guardians of the Multiverse exponentially increases the number of heroes he could call on. Whenever Hal and the other Green Lanterns face DC's next crisis, the light of the Guardians of the Multiverse could very well light them through their darkest nights.