Sasha's father Niko was a former henchman for Professor Pyg until one day the Professor showed up and decided to turn Niko into one of his mindless Dollotron soldiers as punishment for his failures. Once he was finished with Niko, Pyg then turned his attention to Sasha, affixing his poisonous molten face mask to her otherwise beautiful face.
During the police raid on Professor Pyg's labratory, Sasha is taken along with the other Dollotrons to the hospital where she suffers a mental break and murders her own father in his hospital bed. Sasha is saved from incarceration by the Red Hood who shows up and offers to let her join him in his crusade to clean up the streets of Gotham. She accepts and taking on the name of Scarlet she and Red Hood begin cutting a bloody swath through the streets of Gotham.
Although it's presumed that her Dollotron mask was defective and therefore she has not been affected by Professor Pyg's mind control drugs, she worries that her symptoms simply have not manifested themselves yet and she may in some way be impaired. Sasha dreams of somehow someday removing the ugly doll mask and returning her natural beautiful face to it's original condition.
Scarlet Has Not Appeared In Any Other Form Of Batman Media.