The Overworld had invented a battlegear called an Attaching Gun, Chaor needed to get his hands on one so that Ulmar could study it and build more for the Underworld. Chaor sent four warriors to the Rock River Canyon: Swassa, Takinom, Klasp, and Solvis. Maxxor had sent Antidaeon and Tartarek to patrol the Rock River Canyon. They were armed with the Attaching Guns. That's when the four Underworlders attacked. But it was all a setup. Overworld forces led by Tangath Toborn and Raimusa attacked. The forces easily drove the Underworlders out. Sensing the dangers that could come up because of the Attaching Gun, Maxxor destroyed the prototypes.