The Mirrorverse is a verse found within the Primordialverse that is comprised of a glass-like material that is a fusion of Ischyros Matter and Light Matter, each individual particle is a little smaller than a string (refer to Primordium-Particle Fusions for Ischyros and Light Matter). It can only be entered through very ancient mirror relics made of the same glass-ish material, instead of seeing what should be reflected through these mirrors, what is seen is where the mirror will take you, however, the only way to enter is to, oddly enough, smash the mirror, which does not get rid of the image of the area and is now an opened gateway. Opening this is nearly impossible due to the material being part Ischyros Matter. These relics are UNBELIEVABLY old, the oldest discovered one being approximately OYC old.
The structure of this verse up close is very crystal-like and has a slight fractal pattern to it, it is also very small for a verse, only 0.06 ly wide.
There is one being that lives there, however it can only access outside of its dimension using a specific one of the mirror artifacts located in our Omniverse, and even then, it can only see what is outside of it. It is very, very, powerful, and could destroy its own realm in about 14 days, but only wishes for an escape, for something to finally let it free. Unfortunately, none who have helped in freeing him have been successful.