Deep Core

The Deep Core was like the plain old Core, but it was deep. In fact, it was so deep that fish and squids couldn't survive for long in it. This may be related to the fact that it had a black hole capable of planetary annihilation in the middle.

Unlike the regular Core with its Core Worlds, the Deep Core didn't have many planets in its near vicinity for the reason stated above. Nobody wanted to live there anyway, except for the Imperial Remnant, which got driven so far back by the New Republic that they didn't have anywhere else to go.