Persia is one of two new civs coming soon to Civilization 6, Firaxis has announced.
Persia is led by Cyrus II, more commonly known as Cyrus the Great. He founded the Achaemenid (Persian) Empire, which was, prior to the conquests of Alexander the Great, the largest the world had ever seen.
Persia's unique unit is The Immortal, a swordsman replacement with a ranged attack but a strong combat defence as well.
The unique improvement is The Pairidaeza, or Persian Gardens. These tile improvements provide culture, gold and appeal with bonuses for adjacent districts and city centres. The cool thing is over time they provide more yields as you advance through the tech and civics trees.
Cyrus' special ability is Fall of Babylon. After declaring a surprise war, all Persian units get bonus movement. Cyrus also takes less of a diplomatic penalty for declaring surprise wars.
Firaxis said Persia is a civ perfect for the player who wants to build a rich empire, but isn't afraid to launch a sudden, unexpected military strike.
The Persia DLC will be unlocked automatically for those who bought the Digital Deluxe Edition of Civilization 6.
Meanwhile, Firaxis said the Spring 2017 update will come with balance changes, multiplayer changes and a host of bug fixes. That update's for all players. Expect more on it soon.