Pandaemonium is both the name of the Queen and mother of all the demons and the name of their home world, later revealed in the manga as a traveling ship that crashed to Earth. In the manga, the Elders, unable to fix their ship, decided to keep Pandaemonium running by using a human host for the astral body that is Pandaemonium to inhabit. Eventually, the human host would die off and they would have to find a new female host to replace the previous host.
Pandaemonium's current host (in the manga) is Lilith, Chrono's and Aion's mother. Lilith was already pregnant with Chrono and Aion when she was taken to Pandaemonium by the demons and they were the first of Lilth's children to be born. She is also the last host of Pandaemonium. In volume 8, Aion beheaded her and Pandaemonium searched for a new untuned host. Rosette, her soul currently loose from her body, happens to be the only one available for Pandaemonium to possess. Aion, in his desperation, attempts to kill Rosette's body but Chrono delays him long enough for Rosette to return to her body before Pandaemonium can take hold of her. Pandaemonium eventually completely collapses to ruin, being no longer able to run without a host.