DC ComicsWould the existence of another Earth really be such a stretch? Just because it hasnt been mentioned or explored doesnt mean its not there, and Earth-3 has a notorious history in the comics. That Earth is the home to the Crime Syndicate of America, an evil version of the Justice League, complete with an alternate Flash. In this world, hes known as Johnny Quick, a hyperactive killer and thief. Adding credence to his inclusion is another member of the roster, Deathstorm, the dark Firestorm double who we've already seen this season. Alternatively, this alternate Flash could be a Justice Lord, a different version of the speedster that became disillusioned with his heroic efforts and instead began to subscribe to an absolute idea of justice. Considering the preview for the next episode paints Zoom as a serial killer, even if this doesnt totally play out, theres reasons to think that elements of the character will be incorporated nonetheless.