Sally, a Tatar, married a German and changed her name, surname and religion. (Before the Germans were deported from the Volga region in the 40s of the 20th century, there was a fairly large population of Germans who had lived here for a couple of hundred years.) Why did she do it? I like the version (I didn't come up with it) that she thought Dravo was much richer than he actually was because he was a shoemaker and had good shoes. Well, and maybe just love, why not.
I'm not sure it would be to her advantage to marry a German to raise her status. Although the Tatars were definitely second-class citizens compared to the Russians, the Germans weren't doing so well either and overall the Tatars had a pretty good position in society and a strong community.
Was it possible to marry a man of another nationality? It was definitely possible in the 20th century, even in the Russian Empire before the USSR, in the 19th century it depended on many factors. But overall I think it was possible.
Sally was "white passing", but in Enver's case, his non-white genes prevailed and he stood out like a black sheep among the new community in which Sally now lived. In addition, Drago turned out to be not such a rich and successful businessman. And not such a wonderful person at all. So Enver became a burden and a thorn in their side, reminding them of their own mistakes.
Here on the stage (heh-heh) comes Raphael. Her distant rich tatar relative. At that time, the Tatars did not have aristocrats in the classical European sense. But there was something similar anyway. So Rafael is a rich owner of some business that he inherited from his daddy.
In the 20th century, Raphael become a common Tatar name. Although often with vibes of a name that would be given to a "mixed" child or a child who looks "European". (Not necessarily. This is not a strict rule.) Was this name used by Tatars in the 19th century? I'm not sure. But I find it funny and fitting that Raphael is half-demon and has the name of a child from a "mixed" marriage. This coincidence is very suitable for my AU.
So, Rafael is gay and doesn't want to get a wife and have sex with her even to have a child.
But he thinks it would be good to have an heir to the business, whom he can raise according to his (ideal) vision, and he needs someone to take care of him in his old age. (He doesn't like to think about it, but it's the sad truth. :( In this AU, he's very privileged, but still just a human.) And then he remembers Saniya… Now Sally. She has a child, also "mixed" and people say she doesn't like him very much. Ah, that child would be a good buy! Um… I mean, how noble would it be for Raphael to take him under his wing.