This is the first layer of the Abyss, a place that's dark, green, and populated by the undead. Oblivionaire is said to be the one watching over this place, or his dragon, Asorah. Likely where Coralium originates from.
An endless temple city built at the very edge of sanity. The Realm of J'zahar holds the only entrance to where The Great Old Ones dwell. The Gatekeeper is always watching, and nobody leaves the final layer of the Abyss alive.
(This dimension is unfinished, and only contains J'zahar's temple as a structure)
To enter this realm you must fall into the void in Omothol.
Beneath Omothol lies the realm where the immortal souls of evil daemonic gods rest, awaiting their reincarnation. The Dark Realm is where living shadows are born, and the last place a living souls should ever visit, as they will face eternal suffering.