WARNING: The following contains spoilers for the story "The Flash" from Infinite Frontier #0 by Joshua Williamson, Howard Porter & HI-FI, on sale now.
The Flash is one of the most experienced heroes when it comes to exploring the multiverse. Thanks to his connection with the Speed Force, Barry Allen has done the impossible countless times, and saved entire universes with his speed. That experience just earned him a new position within the Infinite Frontier era of the DC Universe, working alongside the multiverse's most powerful group.
As revealed in Infinite Frontier #0, Barry Allen is about to leave his full-time position with the Justice League for a quietly more important role to become the core DC Universe's representative to the multiversal band of heroes known as Justice Incarnate.
In the aftermath of Dark Nights: Death Metal, the DC Multiverse has been reborn and become a part of a greater Omniverse thanks to Wonder Woman inspiring the powerful and mysterious Hands. As a result of the chaos that occurred during Perpetua and the Darkest Knight's rampage through all of creation, it turns out that many realities have been reset, with their full histories restarted. Others seem to still have their consistent histories from before the Crisis and maintain their knowledge and access to the multiverse. But there are still multiversal level threats that require multiversal level responses. However, the House of Heroes, the interdimensional base of operations for Justice Incarnate, has survived and still serves as a home for the team.
The team, composed of members from notable realities across the multiverse, is dedicated to protecting all of creation from ultimate threats. Although the full roster of the current team isn't revealed, President Superman of Earth-23 is confirmed to be a member of the group. It's likely other members of Justice Incarnate who appeared in Dark Nights: Death Metal (such as Captain Carrot and Iris West of Earth-22) are also among the survivors. But they've also got a newly confirmed teammate from the core DC Universe: Barry Allen, the Flash. Thanks to his experience moving through the multiverse and his impressive powers, Barry is the perfect choice to help explore and chart out the multiverse and watch over it as it grows.
This also confirms that the core DC Universe will have a full-time representation among the multiversal team, which it lacked before. In his stead, Wally West will resume his old position as the Flash and protect Central City in Barry's absence. This is still a huge move for Barry, who's effectively become the ambassador of the core DC Universe to the rest of the worlds in the multiverse. Barry will still be able to return to Earth in case of emergencies thanks to his speed, but this gives him a much more important role within the greater DC multiverse. This should help deal with the kind of threats that still exist, and could present a chance for the now regrowing multiverse to be prepared for attacks such as the returned Darkseid and any other possible threats that exist post Death Metal.
This cements Barry Allen in a much more important position within the DC Universe. He could become one of the most important figures in the entire universe as a result. This also makes Barry the ultimate go-between from the core universe to the greater multiverse. Infinite Frontier just placed Barry Allen into one of the most important roles in the universe.