[@Inkdrop]
Alright, let's go with this, then:
Geitumo was used to be dwarven territory a few hundred years before and dwarves of Zwölfberg recently came to claim it back. Zwölfberg is a tiny island nation and Geitumo had strategic importance thus you generally ignored them. This went on for decades but when you engaged in war with the main continent (make up whatever name you want for that faction) the dwarves also declared war on you. They launched a fleet of about a hundred ships carrying over 10,000 dwarven warriors. Their aim is to retake Geitumo for their clans and do it while the majority of your military is occupied with another nation. Thankfully the other enemy is largely landlocked thus your navies are relatively free for the job. You still have some numerical advantage and the knowledge of gunpowder on your side but the dwarves are fully clad in steel and all fired up to retake the land of their ancestors.



How does this sound?
BTW, you can begin working on your army profile and post it in the Characters section. I think 30-40k soldiers at best sound fine.
It really depends on exactly how many of them you think is a proper match for 10k angry dwarves.