Well, I’ve just finished another new piece of GB fan fiction.
Ghostbusters: Realms at War: Several years after the battle with Vigo, the Ghostbusters discover the source of these ‘ghosts’. A world parallel to ours, ruled by a malevolent demon called Pryah Dark. The demon has decided to launch a full scale attack on earth. Now the Ghostbusters will have to pull out every stop to defeat the new threat.
http://www.fanfiction.net/s/5722061/1/Ghostbusters_Realms_at_War