Warning: SPOILERS through Justice League #6
The White Lanterns - the guardians of Life itself - have returned in a big way in the latest issue of Justice League. Given that all life in the universe has been endangered by recent events on Earth, it is not surprising that The White Lanterns should show up to lend a hand. The form in which they manifested, however, was completely unexpected.
The White Lanterns first appeared in the climax of Blackest Night, a DC Comics' event that saw the various groups that draw their powers from the emotional spectrum generated by all sentient life (such as the Green Lantern Corps) forced to unite against a common enemy - the super-powered zombies known as The Black Lanterns. Drawing off the power of Death and the dark lord Nekron, The Black Lanterns grew more powerful with every soul they slew.
In the end they were repelled only after the Green Lantern Hal Jordan bonded with Entity - a being who is the physical avatar of Life - and used its power to resurrect his fallen friends and the villain Black Hand, who had served as Nekron's tether to the world of the living.
The powers of The White Lanterns are immense, yet limited. They can resurrect the dead but only under severely limited circumstances. They can heal the mortally wounded quite easily, however, and can sever the connection between a corpse and the Black Lantern energy that animates them. They can also replicate the unique powers of the individual Lantern corps, since all their abilities comes from the white light of Life which empowers all of the corps.
Justice League #6 finds the team in dire straits, thanks to Gorilla Grodd's newfound command of a Still Force to counter Flash's Speed Force and the sentient star Umbrax, whose invisible light fuels a dark emotional spectrum of repressed emotions that the villain Sinestro has tapped to create an army of lost souls enslaved by their own worst impulses. With their powers largely neutralized by their arch-enemies, The Flash and Green Lantern John Stewart pooled their powers with the telepathic Martian Manhunter. This sent John Stewart around the world at a break-neck pace, with The Flash using his speed to empower a car that runs on energy of The Speed Force as Martian Manhunter linked himself to every person on Earth and shared the heroes' shame and guilt for their own shortcomings while showing how those feelings could be used to drive one to new heights.
Precisely what effect this has had on the total population of Earth is unclear. What is clear, on the final page of the comic, is that the heroes' efforts generated some kind of white light that surrounded the entire planet... and that force-field of light is emblazoned with the emblem of the White Lanterns.
Whether everyone on Earth is now a White Lantern or Earth itself has been awakened as a sentient being as in the case of the Green Lantern Mogo, the next issue of Justice League will be one to read!
Justice League #6 is now available from DC Comics.