[Legionas]

Wow,I could not have broken it down better....but also in the area that was formerly Antrium would be the ideal habitat for a babirusa or tapir of some sort,the Legionasian Amur Leopard,Manchurian wapiti and the Eurasian brown bear.

The native fish:
Dunkleosteus plays a major role in Legionas' history and is farmed in large numbers on the south coast particularly at the border[1 or 2 find their way o the other side of the IDU].The Artic Char dominates the eastern area of Legonas and is a delicacy for many.It is found mainly in R Weriese[A river that runs from Mt Mors Apicem,to the coast].Bluefin Tuna,Rainbow Trout,whitespotted char,Nile perch,minnows,shrimp and many other crustaceans are evident and live in harmony.

Leopard? okay, but see my post to Laeral just above this. Wapiti, sure, that would fall within the 'Red Deer'/[American] 'Elk' group of species that I've already suggested would be represented here anyway. Brown Bear, certainly.
The region probably doesn't have Babirusa, given that the limited range they have in RL is quite some distance from the nearest other RL lands that have given us species, and I suspect that the bits of former Antrium now within your territory are a bit too cold (and/or don't have suitable foods available all year) not only for them but also for Tapir as well: Would you settle for Wild Pig (which is present in the RL Manchuria/Amur area), and maybe a Chalicothere or a Hairy Rhino (which would be about the size of a tapir), instead?

Dunkleosteus? Seriously? Okay, but I'm not going to try explaining how could have survived in the IDU's waters ever since the Devonian Period: As far as I'm concerned, if you really want them then [even IC] they were only incorporated into this region when the relevant "reboot" of history brought your nation as a whole here.

Char certainly, and I've already got some (probably of a separate species) in [nation]The Ursine Northlands[/nation].
Bluefin Tuna, okay, but probably only at the southern edge of your waters and even then the cold current passing southwards from the arctic would limit their activity: Your fishermen would probably have to travel some distance out to the south-west to find many of these.
Nile Perch are probably adapted to warmer climates than yours. Would you settle for something more like the 'Pike-Perch' or 'Zander' of RL, or even for a Pike, instead?

I agree