TLDR version until I have time to rewrite. (maybe still too long, lol)
The Main world in which the Hub exists was ravaged by war between magic users and technology users over dwindling resources and racial hatred. At a point of mutually assured destruction, a group of secret defectors from both sides set up a self-sustaining community deep underground. As their colony began to grow, their small community also became strained for resources. As the surface was no longer viable for resources, they developed dimensional teleportation technology. The dimensional rifts destroy circuitry, capacitors, transistors and any other form of electrical technology on contact. Even living things get severely disoriented and weakened by the rifts. Scouts were tried at first but more than half didn’t return. This was an unacceptable risk so they developed the Golem. The golem is a magical construct that will follow simple commands and provide a psychic link between all of those who have been imprinted on it. If the golem doesn’t get commands within a length of time it will automatically return home. It can also carry an unlimited amount of items as well as people. This allowed them to go on full resource gathering missions almost at will.
It seemed as though the problems of the community had been solved. After years of continuous success, one trip brought a virus back to the community that caused infertility. They examined the peoples of the dimension that the virus came from to find they were all genetically immune after eons of evolution. They community began to breed with the immune population but most of those who were able to conceive, soon miscarried. Those able to carry children to term were greeted with extreme birth defects which caused the infants to die soon after birth. The community was doomed. They had an obligation as dimensional travelers not to spread the virus to any other dimension. They banned dimensional travel and as a result their resources dwindled.
After some time they managed to make the virus no longer contagious and they resumed dimensional travel. However, since it had been years since the last birth, they faced the new problem of an aging and dying population. They began to “adopt” children from various advanced dimensions and educate them in their history, culture, magic and technology. Well, it would seem that most cultures don’t appreciate their children being “adopted” and taken to another dimension. As soon as a rift would open in these dimensions, the members of the community would be attacked almost immediately. The decision was made to no longer travel to worlds once children were “adopted” from them.
With a once again thriving community now made up of many different races, they began to settle into a routine of daily life. After nearly a decade of this seismic activity started to increase around the community. In our world it would be something of a concern, but could be contributed to some kind of tectonic activity and thus could be measured, predicted and prepared for. The world in which the community presides though is unique in that there is zero tectonic activity anywhere on the planet. It is for this reason, the community members collectively panicked. They had no frame of reference. There was no such thing as earthquakes on their planet. This seismic activity could only mean one thing. Someone or something was digging.
The surface-dwelling magic-users attacked first. They rode down in the belly of a massive worm with giant toothy scales covering its body. The magic-users were using the spring almost as fast as it could flow. Whenever a dimensional rift opened the flow stopped for a moment and someone finally noticed. The magic-users thought it was the tech-users stealing from their spring. They followed the spring underground until they found the community. They burst through the wall in the hydroponics sector destroying a good amount of the equipment and crops. The community was not equipped to handle any attack. Some of the community members realized they had no chance quickly and gathered the youngest ones in the medical wing. They barricaded the bulkhead doors and watched from the monitors as magic-users quickly subdued those on the outside with magical beams, blasts and barriers. They stood hovering over consoles trying to make sense of all the technology made within the community over the past few centuries.
The tech-users’ sensors picked up several large spikes of magic use deep underground and they quickly mobilized in a mechanized digging machine. They feared the magic-users were trying to enact a plan to destroy their cities from below. They burrowed fast and with purpose. They honed in on the greatest magical usage as they neared the community. From the surface, the spring reactor didn’t even register on their sensors, but at this depth it shone as bright as the nearest star on their scanner. They rammed into it at full force hoping to take the magic users by surprise. This ultimately was their undoing. As the side of the reactor was breached, the hull of their mechanized mole disintegrated and as the raw magical energy from the reactor fused with their own reactor fuel a great explosion sent a great blue fireball back up their tunnel and vaporized them in one fell swoop.
The breach and subsequent explosion knocked out power in the entire community. Everything went darker than night and the air purification systems ceased to function. The air, now poisoned by the reactor explosion could not be expelled and began to thicken the air. The magic users who could not fly, quickly coughed, fell to their knees and suffocated as the poison coated the inside of their lungs. A few magic users lit magic lanterns to survey the situation. Those magic-users who could still move, gathered their dead and afflicted and retreated back into the belly of the worm. The worm ducked back into its hole and secreted a hardening bile into the opening as it moved to seal the tunnel behind it. The magic users were confused by what just happened but quickly surmised that they must have quashed a forward attack base of the tech users.
After losing communication with their response team, the tech users sent a probe down their tunnel to investigate. What the saw was just charred rubble at the end of the tunnel and a thick blue haze. The damage was too significant to warrant a search for life and the there was no longer any magic signatures on their scanners. They were unsure what happened but it was clear that there was nothing left to investigate. They used the drone to lay charges at intervals up the entire length of the tunnel. In one long simultaneous explosion they sealed the tunnel for good. The community was once again alone and cut off from the surface.
Those of the community who were in the medical wing watched in horror as events unfolded. The walls of the medwing were shielded from all types of scanning. The med-wing also has its own power and air purification. They could survive in there indefinitely, however their food supplies were extremely limited. With 4 adults and 43 children, a decision had to made. They could try to repair the systems outside, but they could not breath outside until the air purification was fixed. They could not fix the air purification until the main power was back online and it would take extensive repairs just to get it to function at all. The golem could be used to make the repairs but as the golem is limited to one command at a time, it would take far more time than they had. So the decision was made to put all children in stasis pods until the community was in enough of a functioning state to sustain them all. The adults would also take turns being in stasis to lengthen the time for their food stores.