I got the impression that the Builders were the "God in Heaven". Say that they forsaw what ever cataclysm happened to the world so they built the Spires for the majority of humanity and they themselves constructed some type of space station for them. Kind of like in Dan Simmons " Illium". Then the Archangels are some type of spaceship or shuttle used when they have to intervene against the Enemy. Whatever that red-eyed thing Folly tangeled with is.