The Flash of Two Worlds, Barry and Jay, have faced several sinister stinkers throughout the years, each using novel approaches to try unseating the Fastest Men Alive. And unlike their peers, they had the means to succeed. For Samuel Scudder and Jonathan Cheval, a similar approach was used with both. Samuel was a criminal trying to find a niche and discovered it using reflection technology through several mirrors, while Jonathan harnessed his incredible aptitude towards optics into various lens-clad weapons out of revenge for being defrauded by criminals.
While Scudder's Mirror Master identity caused Earth-One's Central City terror throughout the years during various clashes with his scarlet-clad opponent, Cheval's rampage of revenge in New York City was stymied by Earth-Two's Hawkman.
Still, each malevolent man achieved riches eventually, Cheval by inventing optical feats of science and retiring to France while Scudder stumbled upon a mirror dimension filled with beautiful women that provided him all the valuable items he could want. For most criminals, this would be all that was needed to obtain, and they would leave behind such ill-begotten careers.
Yet the thrill of crime was to intoxicating for each man that reawakened a criminal instinct. Interestingly, the golden age Flash had already met the Monocle, or rather another going by said name. That Monocle's counterpart was attorney Paul Barrett whom Mirror Master used to imitate various of his fellow Rogues versus his speeding adversary, mentally controlling him much as the original Monocle mentally controlled his victims. Later, Scudder would use mirror replicas of himself, and various Monocles would likewise appear to add to Cheval's reputation as well.
Decades later, motivated out of boredom and the lure of the Secret Society of Super-Villains, the Monocle defeated his old foe and also helped lure Jay Garrick into a trap with the help of the Flash's enemy and Cheval's teammate Rag Doll. Still, he found only the agony of defeat himself just as Mirror Master had during his association with the Injustice Gang. Both felons and their allies faced their enemy's allies in the Justice League and Justice Society, who with each Flash overwhelmed these coy crooks.
Still, both reflective-surfaced rogues continued their alliance with these teams on future occasions although those schemes also fell flat. Like the mirror lens they each used repeatedly.