Threats to the Multiverse: The Tartarus Hole
For various reasons, both political and economical, Inter-Universal war and terrorism is almost unheard of in the Multiverse. Equally rare are disasters that can span multiple Universes. However, such things do exist. Power-hungry nutcases have appeared from time to time with the resources and technology that make them genuine threats to the well-being of multiple Universes. Usually, it takes somebody with equal resources to remove these threats.
One of the biggest threats to the Multiverse is a destructive anomaly known as the Tartarus Hole. The hole is best described as a black hole of infinite size and infinite gravitational force. By the rules of science, such an object can only exist if it is traveling at the speed of light, as explained by The Theory of Special Relativity. Even when Magic gets involved, a Tartarus Hole is still thankfully nearly impossible to unleash. However, there are a few possible ways, though they obviously haven’t been tested.
Unfortunately, I fear I must take full responsibility for supplying what might be the easiest way to open a Tartarus Hole. In my little network of Literary Universes and the attached Dimensions, a theory states that destroying the central hub of the larger of the two Dimensions using the right form of magical energy will unleash a Tartarus Hole. Other ways, across the Multiverse include using magic to break every known Relativity boundary, such as the Speed of Light, in a Universe or trying to destroy a Universe by condensing it into a particle the size of an electron.
Some good news exists: It is possible to stop a Tartarus Hole if it is detected in time. Like black holes, Tartarus Holes have a singularity; the minute point that exerts all of the gravitational force. They also begin their destruction by expanding along only one directional plane, rendering them temporarily flat. If the singularity is attacked in a direction exactly perpendicular to the plane of the Hole by a very powerful expansion spell, preferably one that alters density as well as size, the singularity will grow too large to maintain it destructive gravity and the Hole will dissipate, leaving regular Void behind. Then the job is simply to re-set the Universal or Dimensional Boundary before the void tears something apart.