As part of a behind-closed-doors presentation at GDC 2012, 2K and Firaxis have unveiled more details about the upcoming Civilization V: Gods & Kings expansion scheduled to be released this Spring.

The expansion features the return of Religion and Espionage, alongside nine new civilisations, three original scenarios, 27 new units, 13 new buildings, and nine new wonders.

The new details in full:

Religion

Faith is the currency of religion, and it's accumulated like any other resource in the game.

You can select your Pantheon when you reach 10 faith, which should only take a few turns.

Certain units, like Pictish warriors for the Celts, generate faith when killing other units.

There are 20 different Pantheon beliefs to choose from, such as the God of War or the Goddess of the Hunt.

Pantheon abilities are usually terrain-based. For instance, the God of War pantheon gives you bonus faith if you kill an enemy unit within 4 blocks of one of your cities.

When your civilisation spawns a Great Prophet, you'll be able to start a religion.

There are pre-defined religions to choose from (such as Christianity or Taoism) but these can also be mixed-and-matched and renamed by the player. The Firaxis team likes to call their religion Sidism.

Your pantheon choice rolls into your religion, and you'll also get to choose between two more bonus abilities. The first is the Founder belief, which gives you rewards for spreading the religion to other cities, and the second is the Follower belief, which will confer bonuses to any city (and any civilisation) that follows your religion.

Religion has been designed so that not every civilisation in the game will be able to access it. In a 10 civilisation game, only about 5 will be able to start a religion.

Once you've started a religion you'll be able to build cathedrals in your city, but these are purchased by spending Faith.

You can also spend Faith to build Missionaries, who can spread your religion to two cities. These cost 200 Faith, and during the Renaissance era the demo was generating 10 faith per turn.

Redesigned City States

City states now have a more involved quest system, and can set multiple quests at once.

Merchant city states have also been added, which give exclusive resources to their allies - such a jewellery.

City states can now be bullied by moving military units nearby, and while this causes the city state to dislike you it can yield some pretty good bits of swag.

Espionage

Spies are now controlled entirely via menus, and don't show up as units on the map.

There are three tiers of spy; Recruit, Agent and Special Agent.

Every civilisation gets access to spies as the first civilisation hits the Renaissance era.

An additional Spy is made available from that points onwards as you head into each era.

The British get an additional spy.

Spies can stage coups in city states, as well as rig elections. Their chance of success is based on their individual skill and how long they've been infiltrating the city state for.

There is also an intrigue menu when you've embedded an agent into a city, which can reveal precise information about what other civilisations are up to. This information can also be given to other players.

Military changes