According to ComicBook.com, Magenta will debut in the third episode of "The Flash's" upcoming season. Considering the character's history in the comics as a founder of a new team of Rogues, it's possible she could joins forces with other villains as the "Flashpoint" story arc shakes up the series in Season 3.
In the comics, Magenta (AKA Frances "Frankie" Kane) was an ex-girlfriend of Wally West who gained the ability to control metal, at the cost of becoming completely mentally unstable -- thus birthing the Magenta guise. Though she first appeared in Marv Wolfman and George Perez's "New Teen Titans," the character became more prominent during Geoff Johns and Scott Kolins' "Blood Will Run" arc on "The Flash."
"The Flash" races back to the small screen Tuesday, October 4 at 8pm ET on the CW.