The Coming of the Dark Host is the 8th mission in the Fallen Campaign.
- The Evacuation
- Protect Keran
- Kill both Renegade Mages
- Leave no humans alive
- The Avatar of Darkness must survive
This mission is actually quite simle. At the beginning, two Renegade Mages are positioned at both exits of the cave. They have created a magic field that kills all units instantly if they touch it.
The secret to this mission is simple. There is high ground provided at both exits of the cave. There, you can build Chain Lightning Spires (that are buildable for the first time). Then, the attacking units don't pose a threat anymore.
Upon Keran's finished transformation (it takes 30 minutes), he can make himself invincible for a certain period of time. This way, he can cross the magic fields and kill the Renegade Mages, thereby removing the fields.
You can destroy the Empire bases with a regular army of with Keran alone (he can do this).
There is a small optional mission that isn't even mentioned in the quest log. You have to build 5 Void Walkers and position them on the beacons near the ancient mechanism. Then, it activates and beams units one-way. On the far side, there is a Healing Dust +300, a Mana Dust +125 and a Belt of Absorption.