Warning: The following contains SPOILERS for The Flash season 9, episode 4, “Mask of the Red Death, Part 1.”The existence of the Red Death in The Flash season 9 calls into question the rules regarding doppelgängers in the Arrowverse following the “Crisis on Infinite Earths” event. Granting that the exact rules have been inconsistently portrayed between the various superhero series making up the Arrowverse, the truism that travel between alternate Earths is now all but impossible had been upheld until now. Thankfully, loopholes explanations could explain the apparent inconsistency, ranging from the ill-defined power of the Negative Speed Force to a quantifiable difference between alternate timelines and alternate Earths.
