The Lunar Subterrane

Long has Golbez guarded the location of his domain, a solemn sanctuary wherein he conspired to break the barrier between worlds. It is there, within the recesses of the Thirteenth's moon, Zeromus bides its time, gathering the strength that will see Golbez's plan to fruition. But what else could he be guarding in this subterranean labyrinth? What secrets might be laid bare by those willing to brave its abyssal depths?