[quote=@Nerevarine]
<Snipped quote by Willy Vereb>

How about the Semids? They're right across the sea, and being elves, would probably have no problem trying to incorporate Yllendtyr into their empire (probably the Kingdom of Sem at that time). I also had an idea of them being historical enemies, with something like a founder myth ala Isaac and Ishmael starting their antipathy, and conflicts only keeping it alive.
[/quote]Anyways, that can be also a good idea.
I plan to have Galhonore's territory (the other half of Sotoa Peninsula) to be conquered by the said empire and it only gaining independence later. But as a result it forming into the Galhonore Commonwealth (which is nowadays under personal union with Yllendthyr, Think of Austro-Hungaria or something similar).

So the threat coming from the East could make sense. Yllendthyr unites as their eastern neighbors are being conquered.