The Xenoverse is the second to last finite Archverse. They contain Metaverses which have slight variations in their logical systems.
When a Hyperverse forms, its interior is rife with chaos, and as such, may produce chaos particles. These chaos particles move around at relatively slow speeds. When two particles collide, one will simply invert its direction, but the other will be disproportionately launched in the opposite direction it came from.
Ineviteably, this speeding particle will impact the surface of the Hyperverse, fast enough to break out, and cause a 6 dimensional existence-0 cross section will begin to form and travel in the opposite direction, always expanding as to rest on the surface of the Hyperverse. This is called a Proto-Xenoverse, and after certain large size, it will disconnect from the Hyperverse, turning into an existence-1 Xenoverse and capturing some of the chaos for itself to be used for Metaverses.