The greatest difference between the Scions and the other civs is how the Scions use population, and how they gain it.
As a Fallow civilization the Scions don't need to allocate any of a city's population to gathering food. This means that, given the same population as another civ, Scion cities are far more productive. However, as a Fallow civilization the Scions cannot gain population via food and normal growth. Instead they must lure Awakened from the Bottomless Tomb, create Reborn, or capture cities.
Awakened:
Citizens of long-departed Patria, the Age of Magic's greatest empire, are the the core population of the Scions of Patria. They have been given the Gift, but they still must be brought out of the Bottomless Tomb. Awakened may be "built" in the capital. Structures much like bridges are extended into the Tomb and used to find and ferry the honored dead back into the world. But they are very expensive and inevitably temporary. After a short time they become animate and unalive, like everything in the Tomb, and may no longer be used. Awakened gained this way are expensive. But they honored dead are hard to predict - you'll often be forced to go in after them.
The easiest way for the Scions to get population is for an Awakened just walk out of the capital's Bottomless Tomb of it's own free will. But while the Tomb is bottomless an endless army of Awakened won't be coming: They have their own alien amusements there. The longer they stay the less willing they are to leave.
The frequency with which Awakened emerge is displayed in the message area and can be increased by the player's actions. Building Shrines to Kylorin, Imperial Cenotaphs or Temples of the Gift, Halls of the Covenant, or the Flesh Studio all attract Awakened. Most luxuries will help lure Awakened. Of special note is the "Patrian Artifacts" resource. Only the Scions player can see these resources, and unlike the other luxuries each resource owned increases the odds. The larger, more bustling the Capital the more will Awakened are to emerge. And when society is explicitly run for the benefit of the Awakened, "Aristocracy", Awakened are more likely to come forth.
Reborn:
Reborn are formerly living inhabitants of Erebus granted the Gift and transformed into undead Scions. There are four ways to gain Reborn. First, Reborn can be created from combat with a priest of the Gift - A Legate, a Doomsayer, or a Doomgiver. The enemy unit is persuaded that unlife among the Scions is preferable to their present meager existence. Second, Reborn can be "built" in a city containing a Cathedral of Rebirth. Third, once the Scions have Sorcery and Priesthood a razed city will yield a few Reborn. Finally, the Dark Council generates three Reborn the turn it is established.
Capture cities:
Of course anyone can do this. All you need is a bunch of guys with swords. However, the lifestyles of other civs isn't very compatible with the unlifestyle of the Scions. When a city changes hands to or from the Scions most of the population is lost.
[size=+1]Details on Awakened Spawning:[/size]
The formula determining the odds an Awakened appear each turn isn't complicated, but it is rather long.
The base chance for a Standard-sized world is:
Quick: ~9%
Normal: ~6%
Epic: ~3.5%
Marathon: ~3%
World Size adjustment:
"Population limit" / 40
That limit is 20 for a Duel sized world and goes up to 70 for a Huge world.
The world size also sets a cap on Awakened generation: It ranges from 20 for a Duel world to 70 for a Huge one.
Additive factors:
Capital population / 4
Total buildings:
Gift Temples or Cenotaphs * 1
Halls of the Covenant * 2
Shrines to Kylorin / 2
Resources:
The number of Patrian Artifacts available * 0.75
Then +1 each for having any:
Silk, Gold, Gems, Ivory, Dye.
Multipliers:
Civic: Aristocracy? Then * 1.66
Game speed - the numbers are linked to game-speed production adjustments. Divide by...
Quick: 0.5
Normal: 0.75
Epic: 1.125
Marathon: 1.5
Game turn. Every turn it's a little harder by...
Quick: 0.5%
Normal: 0.25%
Epic: 0.165%
Marathon: 0.125%
Ai mod:
The AI gets a 20% bonus.
Leader:
Korrina has a 25% penalty.