Apparently a simple neutron star, later investigation by the crew of the Nostalgia for Infinity discovered that it was, in fact, a massive alien computer. Linked to Cerberus through a portal -- theorized by Dan Sylveste as possibly being the phenomenon that's study had given the Shrouders their mastery of space-time warping -- it was able to sample individuals who passed through and create sentient simulations of them. It was also able to communicate with its past and future incarnations.
Originally, after the star's supernova, a black hole was created. However, at some unknown point in the future, someone -- or something -- began a process that injected particles at particular rotations along its event horizon, which caused them to travel back through time -- as time and space had become merged concepts so close to the gravity well. Having no effect on past moments of the black hole itself, it did effect its pre-black hole incarnation. During the supernova, instead of collapsing into a black hole, it formed a paradoxical structure unlike anything else in the universe.
A neutron star, at least the crust of one, formed by strange quarks and degenerate neurons. The new creation was capable of lighting-swift computation and possessed the theoretical maximum density of storage of matter.
During their war with the Inhibitors, a faction of the Banished fled into Hades.
Nearly a million years later, Dan Sylveste and his wife Pascale also entered the construct.