Deep in the Batcave vault, Batman has gathered various weapons in case one of his fellow Justice League teammates should ever go rogue. Amongst the contingency weapons is a Sinestro Corps power ring, recovered when Sinestro and his yellow lantern army attacked Earth. During the events of Forever Evil, the evil Power Ring and his Crime Syndicate attacked Earth-0. Theorizing Power Rings ring of power had the same ineffectiveness against the color yellow as Green Lantern, Batman put on the Sinestro Corps ring, and prepared for battle.