[Alneyan]

You should actually be able to do so Deccan, although you would have to suffer the Dominion of either Ashen Empire or Soul Gate. These two themes come in with a lot of nation-only spells, and so you should be able to fully change these spells and the creatures they summon to suit your tastes.

In this case, the problem would be the auto-summon of AE/SG (you could ignore these creatures though), and their population-killing Dominions. Note that the above has not been tested, although I should toy with modding nation specific spells one of these days...