Maria Kyle

Once a fine, high class escort, after Maria Kyle had her second child, Karl, her body changed and she was relegated to a life of a lowest tier East End whore.
But even after she'd lost her touch, so to speak, Carmine Falcone, a regular client of Maria's, occasionally would make excursions to the East End to have sex with her, his money keeping her afloat after her father, Marcus, who pimped her up from youth from nothing to the upper levels of her heyday, died from a cocaine overdose. 
This affair quite possibly resulted in the birth of her third child, Selina, as she was almost exclusively servicing Falcone at the time, after which point he abandoned her as he did not want the consequences of an illegitimate child on his empire.
She was first impregnated by her own father, who routinely physically and directly sexually abused her in addition to selling her body. The result was Maggie, who exhibited no outward signs of his lineage but would grow to be incredibly unstable.
Eventually, the three children would be rightfully taken from the oft-negligent Maria by Child Protective Services, with Maggie eventually being put in a Catholic boarding school, and Selina and Karl ending up separately living on the streets.
Maria would eventually be killed at some point in Selina's late teens by a young Roman Sionis, who had picked her up under the guise of being a client, only to make her one of the first victims of his torture and killing.