The Phase is one of the most important events in Styx history.
The Phase is basically the mass breeding cycle for the Styx. No one knows what causes it; more than likely it is a biological clock. When it is time, pheromones cause the Styx women to transform into insect-like forms and begin laying eggs inside of their victims. The Styx Warrior larva then emerge. They meta morph into a pupa, then emerge as warriors and if that does not go as planned, they are to change into the Armagi.
Supposedly, the very first Phase occurred in prehistoric times. This Phase caused the extinction of the dinosaurs.
During the next Phase, the Neanderthals were the victims. They gave the Styx their human appearance.
The supposed third Phase took place in the fifteenth century in Romania. During this time, Prince Wallachia, A.K.A. Vlad the Impaler, promised the Styx a safe place to carry out The Phase and a supply of human bodies so he would be rid of his enemies, the boyars. After The Phase began, Vlad ordered his knights to slaughter the Styx newborns. They killed every one and burned the remains before they changed, thwarting the Styx's plans.
Spiral basically covers the events of the fourth Phase. The Styx attempt to use humans and Colonists as hosts for the eggs. Will and his group try everything they can to stop this Phase from being carried out. Though they stopped two groups of Styx that were carrying this out, a third group continued. At the end of Spiral it seems that this Phase may succeed, as the first of the Armagi were born. However, in Terminal, Elliott returns the trident to the Earth's guiding Tower, which transports all the Styx to the plague-infected inner world. The Armagi are destroyed and the fourth (and presumably last) Phase is stopped.
- The Book of Proliferation covers every detail about The Phase.
- The Phase is said to be the most powerful force the Styx will ever feel. Eddie says you can sense it with every single cell in your body.