Actually, Al Mansoor was the greatest Abbasid Caliph. There are millions of people claiming Abbasid descent in the direct male line. However, not all of them are real, as was shown by DNA testing. People that are considered Abbasids include the President of Sudan Mr. Omar Hassan Al Bashir. Emirs Ruslan and Iskander are from Moscow, Russia, but their paternal ancestors are from Damascus, Syria. Currently they are residing in Moscow. And no, they have no connection to the Caucasus region.