Delphic Expanse

The Delphic Expanse, also known as the Expanse, was an area of space in the Alpha Quadrant approximately 50-light years from the Sol-system and covered over two-thousand light years in size. For centuries it was unreachable or too dangerous to the galaxy at large to explore but became the second and by far the bloodiest battlefield for the Xindi Conflict. Following the end of the war, the Delphic Expanse ceased to exist and the region's violitile nature allowed it to again become one with the galaxy.

Composition
Entering and exiting the Expanse was extremely hazardous due to thermobaric clouds which surrounded the area. This thick layer made it extremely difficult for only the most heavily armored ships to enter and exit, and took at least six hours to traverse at sub-light velocities. Thermobaric clouds also are prone to subspace eddies, which can be attracted to the warp fields of passing vessels and pull them into the clouds like a magnet. Without the proper shielding, these ships are pulled to their demise.

Speeds faster and up to full impulse are difficult for ship's intake manifolds to process due to the thermobaric gases. In addition, the thermobaric clouds prevented ships engaged in combat from acquiring a precise weapons locks, necessitating a reduction in the distance between the ships.

Travel through the Expanse was further complicated by numerous subspace anomalies which littered the area at random; these anomalies were responsible for numerous inexplicable events. In several instances, the laws of time and space could cease, be reset or even go wild. These anomalies often led species from outside of the Expanse to ban entry, as the safety or even survival of those entering could not be assured.

Size
The exact dimensions of the Delphic Expanse remain unknown, during the 22nd century, Vulcan scientists estimated it to be around two-thousand light years in volumn. Whilst entry of the Expanse is incredibly dangerous, numerous habitable worlds, stations, outposts and species do make this dangerous zone their homes.

Native Races​
The Delphic Expanse was a vast region of space, home to numerous species.
 * Cardassian
 * Gorn
 * Haradin
 * Illyrian
 * Inkaaran
 * Kovaalan
 * Loque'eque
 * Oran'tako
 * Skagaran
 * Triannian
 * U'tani
 * V'radian
 * Xathanian
 * Xindi

Worl​ds
Because the Delphic Expanse covered a volumn of space of over two-thousand light years, hundreds of stars and planets fell within its boundaries.
 * Arakon
 * Azati Minor
 * Azati Prime
 * Calindra
 * Cardassian Prime
 * Celia
 * Cleon
 * Galen
 * Gorn
 * Herva
 * Illyria Prime
 * Inkaara
 * Kovaalan Nebula
 * Muratas Cluster
 * New Xindus
 * Oran'taku
 * Penthara
 * Triannon
 * V'radian
 * Xanthan
 * Xindus

Mass Relay Net​work
The Delphic Expanse was a rarity as it contained an entire network of Mass Relays spread across its two-thousand light years, completely isolated and self-contained from the rest of the galactic network. No outside Relay could lock onto a Delphic Relay and vice versa.

In total there were over 78 Relays dispersed across the region, but less than 37 of them were active. Counterance to that, every Relay inside the Expanse was a secondary relay, it could link to any other relay over shorter distances, only a few hundred light years, but not to a partner relay over several thousand light-years.

The entire Delphic Relay network was destroyed by Captain T'Pol abroad the ICS Galactica in 2157 during the Attack on the Azati Minor Relay.

History
It is theorized that the thermobaric clouds of the Expanse were formed three-million years ago when several dozen stars of varying composition and size were simulantiously destroyed and their collective energies poured inward via some sort of stellar manipulation. It was assumed the race attempting to do this was trying to destroy the Mass Relays in the Expanse of their era.

However the Reapers managed to halt this, by reconfiguring the Azati Minor Relay as a would be siphon to absorb all that energy and translating it through the other Relays in the Expanse on a never ending loop where it could never materialize. The imploding energy wave was frozen in its tracks, held in place by the Azati Minor Relay as the center of the loop, the rest of the energy loop forever cycling through the other relays in the Expanse. As a precaution, the Mass Relays in the Delphic Expanse were isolated from the galactic network at large, for fear that if the energy loop were ever disrupted it, it could decimate the entire galactic network.

A side affect of holding the energy of several dozen stars in a never ending loop was a bubble of thermobaric energy began to form around the Relays, attracted to the power but kept at bay by the gravity halos of the same Relays, creating the clouds that would soon isolate the Delpic Expanse from the rest of the galaxy.

Millions of years later the Reaper Monarch, encouraging the New Xindus Cooperative to begin expanding militarily for it to use them as a puppet force to invade the Citadel, reactivated a portion of the network, shifting the loop onto the remain half of the inactive Relays but keeping the Delphic Relays seperate from their galactic counterparts. The New Xindus Cooperative began a wave of conquest across the Expanse using the Relays and that soon brought them into war with the Interstellar Coalition, starting the Xindi Conflict of the 2150s.

The Expanse's orgins were unknown until theorized by Captain T'Pol during the final hours of the conflict, after studying the thermobaric clouds throughout the entire later stage of the war, along with recovered archeological texts from all over the Expanse, she managed to determine the nature of the clouds and their orgins.

She also theorized how to disrupt the Relay loop and during the Attack on the Azati Minor Relay disrupt the loop just long enough reverse the energy while dialing up the Relay's gravitional pull. The energy was not enough to destroy the Relay's outright but damaged them enough that their own gravity halos caused everyone of them to implode.

Without the Relays, the thermobaric clouds had no energy to sustain themselves and began to rapidly fade, before finally the Expanse was no more and regular travel could resume to the outside galaxy.