The Metavasis was an ancient research vessel created by the extinct Kathol over one million years before the Extant War. Believed to have potentially been the source of phase engine technology redeveloped by the Charon of the Second Charon Dominion, the Metavasis was a mobile laboratory utilized by the Kathol in dimensional experimentation, through which the Kathol inadvertently discovered Otherspace galaxy and the rouge planet of Otherworld.
Unlike the technology developed by the Charon which was based upon the Kathol phase engine design, the Metavasis was capable to traversing between the realspace galaxy and the Otherspace galaxy without the requirement of a dimensional rift or fissure, such as the Hellmouth. Instead, the Metavasis created spacetime rifts by "shifting" into Otherspace via phase space, thus enabling it to enter into Otherspace from virtually any location in realspace.
The Metavasis was discovered by the Galactic Emergency Coalition through the aid of the adherents of the Void of Animus following the Extant War, and due to the extent of its capabilities relative to the ongoing conflict with the Charon Dominion, was thereafter considered to be a superweapon, and classified as such.