The Cossacks Are Coming to Europa Universalis IV

From Paradox:
For centuries, the European steppes were dominated by a unique warrior culture. The Cossacks were fiercely independent soldiers, and some of the elite cavalry of Poland and Russia through early-modern history.
 
The Cossacks, the newest expansion to Paradox Development Studios’ best-selling historical grand strategy game Europa Universalis IV, pays homage to this legendarily proud people with a ton of new features that enhance the diplomatic game and give you new things to tend to during peacetime. The Cossacks will come to digital retailers and the Paradox store in late 2015.

The central new mechanic is the Estate system. You can assign control of your provinces to local factions – priests, nobles, or even Cossacks! – sacrificing some income in the name of lower unrest, more manpower or cheaper cavalry. You must keep an eye these Estates, though! If they get too strong, they may make a move on your throne. If they feel neglected, they may interfere with efficient governance.

 
Other features include:

• New Diplomatic Options: Let the world know what you think of your neighbors by setting a public attitude to foreign powers.
• Tell The World What You Want: Designate neighboring provinces as “places of interest”, build trust with other nations, and entice allies with the promise of land for their support.
• Tengri: Tengri is now a Syncretic faith, allowing it to tolerate a secondary religion as if it were a national faith.
• Horde Unity and Razing: Nomadic nations now must pay attention the horde unity of their tribes – a unity that can only be maintained by the occasional pillaging
• Improved Culture Change: You can now restore a previous culture to a converted province, or convert a province you hold to a culture that is not your own.
• Native Policies: Set your policy for colonial encounters with natives. Are you focused on quick subjugation, peaceful growth or trading advantages?
• Improved Espionage: New spy actions allow you to study the technology of more advanced countries and prod your rivals’ subjects towards independence.