The Backstory of the Layers is actually very simple. There are four Layers of Time, and four factions/species that can travel between The Layers. The Faction Wheel at the right shows the four factions, and their alliances/enemies. The Shades symbol is the Blue Aerrow, the Attelles symbol is the Yellow Scorpia, the Eus are symbolized by a Silver/Green Arc, and the Nivus Symbol is the Red Dual Spear. The Shades and the Eus are aliied, and the Atteles are allied with the Nivus.
There are four planned books (one for each faction). The first two are The Shades, and The Attelles. Currently Book I is about halfway done.