Portal Dimension
Also known as "Underspace", the Portal Dimension is a bizarre extradimensional realm exists parallel to our space-time continuum. Unlike our own space-time continuum that has four dimensions, Underspace is a 12-dimensional space and timelike continuum.
Discovered at a relatively early date by the United Orcs, the science of breaking through the underspatial boundary and sending matter and energy into this new dimension was refined by UO scientists. This technology eventually culminated in the Plasmasphere Drive, an FTL jump drive that allowed starships to enter the Portal Dimension at will.
Exploration
During the early expansionist era of the United Orcs, the Royal Space Administration sent hundreds of volunteers to explore the Portal Dimension and chart out possible routes for travel back to realspace through the Gateway Device. Many never returned and were presumed lost forever in the dimension's nightmarish fractal hell, although some later resurfaced in unexpected places all around the Galaxy.
It was soon discovered that in Underspace, normal galactic locations were warped in an extremely strange, but logical way. Hundreds of scout ships were sent to the Portal Dimension to map the optimal exiting points, and more than 80 disappeared, possibly beyond the Rim, or to somewhere even more exotic.
Military use
The use of the Portal Dimension gave travelers the ability to perform surprise attacks on enemy targets, as the exiting point was impossible to calculate without specific maps.
The underlying principles of dimensional travel were also used in the "reality storm" weapons developed by the V3 Alliance, the most well known being the enormous Planet Eater Array.
Structure of Underspace
Underspace has been described as a "fractal reality", crisscrossed by interdimensional passages governed by complex dimensional mathematics. They are vital to travel throughout this strange parallel plane; travellels deviating from these charted routes risk getting immediately and irreversibly lost in dimensional space.
Many star systems are linked by Underspace passages, which significantly speed up travel time.
