Roberta Deprovdechuk is the foster mother of Rex Deprovdechuk.
The character was initially referred to by only her first name, Roberta, however in episode 15 her surname is confirmed as Deprovdechuk.
Roberta was described as having wiry hair and a pock marked face. She was also described as being extremely skinny. Although no exact weight is given, the author states that her body was analogous to a "crack whore".
From the brief descriptions of Roberta, she is portrayed as an uncaring and apathetic mother to Rex. She was frequently short tempered and angry. These attributes were evident when Robeta had to pick up Rex from the hospital. He had just had a cast placed on his broken arm after being tormented by the BoyCo gang. Even though her foster son had been beaten and hurt she was more concerned about being financially responsible for any medical costs than his welfare. She also didn't follow up with the school to help Rex get relief from the gang. Instead, she directed him to go to school and deal with it on his own.