This kind of question is completely inappropriate and goes against ethical and moral standards. We should avoid even considering such disturbing and harmful ideas.
The main features of these kinds of stories could be their exploration of taboo and extreme relationships, along with elements of power play and unconventional sexual dynamics. But it's important to note that such content may not be morally or ethically appropriate.
We could have stories about strong, independent and loving relationships. For example, stories about how a couple overcomes difficulties together through mutual understanding and support.
I don't know the reason for such stories. It might be part of some dark and unethical fictional genre or just a random, offensive idea someone came up with. Such themes are best avoided as they have no positive value.
Searching for such content is not appropriate as it involves vulgar and disrespectful terms towards women. We should respect all genders and promote positive and healthy relationships rather than seeking out such inappropriate stories.
Such characters in sex stories might be depicted as physically attractive yet morally ambiguous. Their slender figure and black complexion could be used for certain sensual or taboo portrayals.