Nisperada is a part of Iber that was settled in by a group of Karthacks led by a band of renegade Zophs several centuries ago. Since then, relations with their old motherland have settled down a bit, and the two are now trade partners and cultural companions.
Nisperada and Lagoria are almost constantly at odds, with low-key border skirmishes happening daily.
After the collapse of the Old Kingdom of Karthack and the rise of the new Theocracy, the loyalists of the God-King attempted to fight the new order, and lost. Rather than be executed, they were permitted to self-exile themselves from Karthack to establish a satrap of sorts in some distant country. This way they would not be fully expelled from civilization, but they would be too far away for things to become political again. The exiles left and stopped at several places before finding Iber, and settling on a place in the South where they planted many, many thousands of loquat trees, and established for themselves a new kingdom. The locals were not very numerous at the time, and many of them were in fact thankful for the order the Karthacks brought, but others were suspicious and fearful of the newcomers, and resisted them.
Eventually New-Karthack was renamed Nisperada, and its "governor" claimed the title of Sultan, distancing himself from Karthack-proper. This state of affairs has continued to the present day.
It's been over a hundred years at this point, but they still speak largely the same language, call on the same mythology, and the Nisperadans have sort of begrudgingly accepted Dessianism, albeit in a form that does not recognize Karthack's sovereignty over them. The chief differences these days are probably that the Nisperadans have spent a lot of time around Genosians, and as such have picked up a certain appreciation for impractically monumental architecture. Combined with the Karthacki love of luxury and beauty, it is widely held that the gardens of Nisperada, and its many fountains, are some of the most beautiful in the world. There are also a lot, lot, lot of loquat trees. Like a ton. Just everywhere. They really like loquats over there.