 While on Earth battling the Black Lanterns, Saint Walker's ring was activated by Ganthet to deputize Barry Allen the Flash as a Blue Lantern.Barry Allen under Saint Walker's tutelage rescued Bart Allen from being a Black Lantern.The rest of the Blue Lantern Corps worked with the Green Lantern Corps to destroy the millions of Black Lanterns coming from the Black Lantern-recreated planet of Xanshi.