Europa Universalis IV: King of Kings includes major updates for:

Persia

- Use the influence of Persian art and culture to bring neighboring kingdoms into your orbit. - Over 70 new National Missions - Unique mission choices depending on the state religion - Sunni, Shia or Zoroastrian - as well as Centers of Reformation and other ways to expand the faith. - New National Idea sets, unique Government Reforms and unique Estates and agendas.

Mamluk Egypt

- Over 30 new National Missions - New Diplomatic options including exporting Egyptian grain and promoting the Hajj. - Unique Mamluk Government Reforms, Mercenary Companies and Estate Privileges. - Option to Westernize Egypt.

Byzantine Empire

- Over 60 new National Missions - Unique Government Reforms and Estate Privileges - New Subject type - the Pronoia - Over 50 new Byzantine themed events and 10 new Decisions

There are also changes for

- Armenia and Georgia: Two Christian kingdoms, pinned between rising empires - Arabia and Yemen: Competing powers on the Arabian peninsula, guarding the holy sites of Islam and the trade routes to India. - Ardabil: A major seat of Iranian culture, and the origin state of modern Persia/Iran. - Aq Qoyunlu and Qara Qoyunlu: Turkmen middle powers resisting Ottoman expansion before the unification of Persia.