Microverse

The microverse, as coined by Dr. Ryan Choi and initially referred to as the atomverse by Ray, is a nanoscopic dimension existing within the multiverse. It is accessible by shrinking to a nanoscopic size, as the dimension is essentially visible to the naked eye.

History
While developing his A.T.O.M. Exosuit, Ray accidentally shrunk himself to such a nanoscopic size that he accessed and was sent to the microverse.

During the Anti-Monitor Crisis, Nash Wells, Ray, and Ryan Choi built a device that can eternally shrink an individual once activated. This invention was used on the Anti-Monitor, sending him to and trapping him in the microverse for all eternity.