Dark Invocation
Dark elven Disciples can pray at Shrines to produce Faith.
Faith is a third racial resource used to unlock new Cult technologies.
Divine Favor
Investing faith into one of four Cults increases favor with one of four elven deities.
This allows you to utilize the Divine Favor mechanic,
which lets you use powerful global abilities at the cost of Faith.
Artisanship
Dark elves have no regular shops.
Instead, they rely on talented Artisans to craft items for their heroes.
They also harvest a bit more lumber than usual.
Ritual of Evocation
Instead of upgrading their main building, the Shadow Covenant performs a
Ritual of Evocation to reach the next technology tier.
Their main building can still function while this is happening,
It can produce workers, attack and cast spells.
Teleportation Link
Dark elf main building - Nexus - can be linked to other Nexuses via a
Teleportation link, which allows you to teleport your units between bases.
Daemonic Invocation
Dark elves can initiate summoning rituals at Shrines and Nexuses.
This grants them a unique way of training additional units:
Imps are summoned at Shrines and spawn in pairs,
Incubi can be warped-in almost anywhere on the map,
etc.
Unit Promotions
Some units can be upgraded from one unit type to another.
Some promotions are meant to give you a smoother transition to later game,
Other promotions serve as the only way to acquire certain units,
And others are just straight up upgrades.
Shared Abilities
A lot of units share common passive abilities with each other.
These include Armor of Dread for Dread units, Manaburn for Demon units,
Shadow Strike for Shadow units, Baneful Poison and Spider Venom for Spider units,
etc.