This article contains spoilers for Green Lantern #7.
In an unexpected twist, Darkseid has just created the first of a new generation of Green Lanterns. The Green Lantern Corps is facing its darkest days yet. The Power Core on Oa has been destroyed, stripping almost every Green Lantern of their powers. The surviving Green Lanterns are scattered across the galaxy, suddenly vulnerable, and they naturally have a lot of enemies. Already bounties have been placed on the heads of the Green Lanterns, and they're being hunted down.
John Stewart is attempting to rally the survivors, and he's gathered together a group of veteran Green Lanterns to respond to crises and rescue their fellow Lanterns. They're currently on their way to the planet Anacitus, in response to a desperate cry for help from the Green Lantern Kilowog. On the way there, John Stewart finds himself confronted by a mysterious being named Lonar, one of the New Gods of New Genesis. "I'm here to watch you save the universe," Lonar tells Stewart. "Or destroy it. One or the other." Those ominous words launch Green Lantern #7, by Geoffrey Thorne and Tom Raney.
Lonar is the God of Journeys, and he transports John Stewart back in time to the first encounter between the beings who would become the Guardians of the Universe and the New Gods. Stewart initially watches this ancient war, but he finds himself unable to resist getting involved when a New God named Uxas cuts loose with a weapon called a Soul Cannon. "That weapon isn't the Omega Force," Lonar tells him, alluding to Uxas' destiny to become Darkseid, "but it will destroy what it touches nonetheless." John Stewart dives in, and is blasted by the Soul Cannon... only to be transformed by the experience. As Lonar explains, John Stewart has just evolved into something new.
Lonar is the God of Journeys, an agent of change and evolution. He clearly took John Stewart to the right moment in history to ensure he was exposed to specific energy that would, in his words, "evolve" the Green Lantern. The color scheme of John Stewart's new costume suggests this evolution has transformed him into the first of a new generation of Green Lantern; note the shimmering sphere of energy in Stewart's chest, suggesting his body has now become a power battery itself, no longer needing the Power Core on Oa.
The current crisis has brought the Green Lantern Corps to the brink of destruction, but Lonar clearly believes that now - even as the Green Lanterns are being hunted - they can change and evolve. His words suggest this is a turning point in galactic history, one that will either save the universe or destroy it, presumably depending on whether the Green Lanterns learn how to tap into the same power John Stewart now wields - and what they choose to do with it. It is ironic, then, that the key to this evolution was found millennia ago, in the being destined to become Darkseid, whose mysterious Soul Cannons were just what was needed.