Mirror Marauding Menaces Week: Chromatic and Monochromatic

These twin masters of light had discovered a curious side-effect to their dappling in the fields of chromatic and monochromatic marvels, that is to say their control over colors and darkness, that said energies provided gateways into parallel dimensions. The Shade of Earth-Two was able to bridge the gap between universes using his Ebony Cane to access the Dark Dimension, although initially this spawned shadow creatures, including fellow fiend "The Dark" who was an old adversary of the Ray. Later, Shade was able to personally teleport to Earth-One himself, and did so to battle...himself.

The Rainbow Raider used his techniques to flood his dimension in black-and-white while releasing the colors from his hometown of Central City on Earth-One onto the corresponding Keystone City of Earth-Two. What he failed to anticipate in his endeavor was that this would run counter to the sinister schemes of his counterpart the Shade, who sought out the means to restore balance to his own world so that he may wield darkness once more, and so traveled to Earth-One. 

Seeing no other option, the Shade sought out his former foe the Earth-One Flash, who had twice previously teamed up with his own Flash to defeat him. Together, Shade and Flash turned the tides against the Rainbow Raider, by reversing the Raider's colorful transformation of the Flash using the darkness from Shade's cane. 

Whether the Raider would later discover that his own terrible twin was the cause of his plan coming unraveled is unknown. The Shade persisted in his attacks against both arch-enemy along with the Flash's allies in the Justice Society, both as a solo operative and as a recurring member of the Injustice Society. Included in the Shade's travels was when he and his cronies Fiddler and Icicle were recruited by Darkseid to help the dark lord retake his planet of Apokolips, and transplant that world to Earth-Two's universe in its place. This too was thwarted by the Justice Society and Justice League.

As for Rainbow Raider, he would continue to have rematches with his own Flash, although he joined forces with other villains such as Doctor Double X and his fellow Flash's Rogues Gallery felons. During these occasions, he'd also encounter allies of the Flash in his teammates Batman and Green Lantern.