Muscovy (aka, Russia) is another fantastic campaign.

It will be a literally different in 1337 than to EU4 in 1444, but the broad campaign themese remain the same; you are the Slavs, a Christian people living under the oppressive rule of the Mongolian and Turkic Khanates, which control much of the area. You will, over time, grow in power and consolidate the other Slavic nations around you-before finally taking the fight to the Mongols.

If successful, you will be in a fascinating position; a vast Christian realm with the vast steppes to the east of you. Consolidate the lands to found the Tsardom of Russia, slowly make your way east through conquest and colonisation, and declare yourself as the "Third Rome"-potentially even eventually marching south to destroy the Ottomans. Kino campaign.