The Al Ghuls (and the League of Asassins as a whole) are anyway wired mix of a lot of asian pulp sterotypes.
I mean they are supposed to be from the middle east, but their basis in is typically in the Himalayas, their "foot soldiers" wear typically Japanese "Ninja" weapons and cloth, and the more important Members of the LoA seem to come anyway from all over the world.
And Since Nolan, the Live Action adaptation seem to usually go anyway with idea that Ras Al Ghul is nut a single Person, but the Title of the current Leader of the LoA and that there have been several holder of this title over the years.