Fall of the Jinn
During the reign of Gideon II, all was not well amongst the efreet. A series of slights, skirmishes, and diplomatic bungles had driven the efreet of the deserts to a state of near-war with the forces commanded by Gideon II, then-Emperor. It is said by some that the gods themselves intervened in the matter to prevent war; and, if true, then it was the last time the Sept deigned to interfere so directly.
The Emperor backed off from his bluster, and the efreet made plans to peacefully depart – not just the desert, but the planet itself! With the assistance of a number of mages and priests of the Sept, a number of large, temporary portals were constructed, and the assembled efreet – thousands in number – packed up their belongings and stepped through. The transportation took place in several stages, over about a decade, the last sortie taking place years after the death of Gideon II.
The efreet relocated to a sweltering planet of fire nearer the sun, and built colonies there. To this day, that world is ruled by the descendants of the efreet; their merchants occasionally come to earth in massive skyships of burnished bronze, once every few generations; they remain a few weeks to trade, then return to the skies.
The departure of the efreet from earth had some unanticipated side-effects, however. The efreet were the most numerous of the jinn on the planet, and without that representation, the rest of the jinn were bred out of independent existence within a few centuries. There are a number of cities and settlements around the world where people claim descent from the jinn, but a full-blooded jinn of any clan is a very rare thing indeed; some subtypes may even be completely extinct.