Rose Forrest of Earth-One and Rose Canton of Earth-Two were counterparts who themselves had twins... evil twins to be precise.
While Forrest experienced a psychological split when her father, a police officer, was murdered by the criminal gang known as the 100... for Canton it was a childhood affliction that manifested when she became infected by a toxic thorn which imbued her with superpowers.
While the former became a heroine of Metropolis, even garnering the respect and admiration of Superman, the latter was a villain in Keystone City, bringing her into repeated conflict with the Flash.
We've previously considered the history of these two women, and a twice-told-tale of the Thorns, as well as the romance that one had with the golden age Green Lantern, now we consider another dynamic of these femme fatales.
On Earth-Two, Rose and Thorn were actually separate women as Thorn's physical form manifested when Rose was unconscious, and visa versa. She had oscillated from Rose's blonde self into a red-haired and brunette version at different times. Eventually, she was captured and taken by the Flash's friend Wonder Woman to Reformation Island, where over a period of two decades Rose regained mastery over herself, with Thorn purged.
At least, for awhile. Eventually returning to America, she sought out the man who had brought her to that Island, Flash's other ally Green Lantern, whom she fell in love with. Assuming a new alter ego of Alyx Florin, she gained the trust and love of Lantern's alter ego Alan Scott, whom she surmised was his secret identity. However, on their wedding night, her intense feelings for him awoke the Thorn, who nearly killed him. Deciding to "kill" Florin, Canton retreated until one day the Thorn grew dominant in both Rose's body and her own. After a defeat at the hands of Flash, Green Lantern and the Justice Society... Thorn was captured although Rose somehow escaped and retreat to the island where her sister was born.
There was another women slated to be the Thorn on Earth-One, years earlier. Outfitted by a costume maker by the name of Albert Talbot, who had been working for the 100, he initially wanted the lady to rob from them as his cut from his bosses wasn't big enough. However, he soon became more prominent in their organization, and withdrew his offer to her.
Years later, captured by Rose's Thorn, Talbot summoned his former ally to visit him in prison to tell her his story. Apparently, Forrest obtained his weaponry and one of the Thorn costumes. Seeking retribution, the woman enlisted her daughter Pythona, a local dancer, to steal from Thorn as the newer and wickeder Thorn,
However, a hit man sought out Pythona while wearing the Thorn costume, thinking she was the 100's arch-enemy. Saved by her opposite number, Pythona parted from her "twin" seemingly abandoning her claim on the Thorn identity. This mysterious woman, with no other name, is the doppleganger to Alyx Florin who had been born on Reformation Island, the civilized version of the villainous Thorn. And as for Canton/Florin, this amalgamation of conflicted women perished saving her family from the Thorn's attack on Alan and their two children, Jade and Obsidian.