Modding nations into different Eras

[Edi]

Zargen, easier for you if you change Ashen Empire to the middle era, where it more or less belongs. I made an Ermor Restoration mod where Ashen Empire is in Middle Era and Broken Empire is in Late Era, thematically changed. It's still pretty much beta, but you can copy the part of it that changes the eras, because you need to reassign all the text descriptions too.

You can find it here

EDIT: Alternatively, you can take a look at how I did the switch there and change the Marignons around the same way.