The newly appeared towering giant called himself the God of Time, Tempus Fuginaut. He had paid an enormous price and risked his life just to meet Wally.
Because Tempus Fuginauts were not unique—every member of their race bore that name—he was forbidden by their rules from appearing in a world that contained an Otherworld Variant.
Yet he had come from the Dark Multiverse, violating his people's laws to arrive at Earth-0 of the Main World.
Though he had not yet encountered the Tempus Fuginaut of this world, the existence of two Gods of Time violated multiversal rules. It was effectively doubling the number of Time Streams on Earth-0, and the act had already severely injured him. He could not remain here long.
After a brief explanation, he swept Wally and half his cell away into the Dark Multiverse's selection interface and gave The Flash a mission.
Not long ago, a great deal of dark mysterious matter had appeared here. It had begun corroding the numbered universes of the Dark Multiverse, like enormous black nets wrapping around one Earth after another before assimilating and staining them black.
Once the entire Dark Multiverse yielded to this deeper distortion, the Light Multiverse would inevitably be destroyed as well. The scales would lose their balance, and then everything would be over.
The Batman Who Laughs would win.
At present, only Wally West could stop it. The other Speedster Heroes lacked something Wally possessed: the "darkness" that allowed him to merge into those worlds.
Thanks to the God of Time, Wally would have five minutes on each Earth to save it. That was the limit. Once those five minutes were up, the world he was in would fall completely, and even time could not be reversed.
After explaining the situation, the Time God conjured a