As I continued to watch the video, the implications of the reaper war became apparent. Wraiths and Phantoms would be waiting for invasions constantly on edge. From what I gathered the Invasions would be similar to a covert operation in modern day combat.
You would have an unknown force that would wreak havoc in your domain. Phantoms would be like the mayors for each zone. The Wraiths both their citizens and soldiers. Specters on the other hand would be the ones like adventurer parties in novels that went to slay the dragons.
The clear division of roles allowed for responsibilities to be black and white. Everyone would know what to do and why. In a perfect world, the roles should have been reversed. You would take most of your military might to attack and reserve a few to defend.
But if Lilly and her white uniformed posse were all just Phantoms, I could not even imagine how powerful Specters would be.