Spoiler: QuinnThe High Priest replies in a low, dangerous voice which rises into an unearthly crescendo. ďWho am I? I? I am the King in Yellow, the true lord of the Dimension of Dreams! None shall dispute my rule here! MY NAME IS TOO POWERFUL FOR MERE MORTALS TO BEAR IT! TO LOOK UPON MY VISAGE WOULD DESTROY YOU, BODY AND SOUL! MY TRUE FORM IS INCOMPREHENSIBLE; INDESCRIBABLE TO YOUR MIND! I AM THE HIGH PRIEST NOT-TO-BE-DESCRIBED!"Spoiler: OOCThink similar to Galadriel in this scene.
Indeed, just hearing him speak so, Quinn's mind strains to concentrate on the words and verges on breaking. He is certain that should the Priest will it, he would truly go mad simply by remaining in his presence.
An echoing whisper of the High Priest's last words reverberates for several moments before he speaks plainly again. "But I digress. Even I must rely on inferior beings to accomplish my goals. In exchange, I offer you power. Power unlike any you have tasted before. And I shall grant you a wish, should I find your service pleasing to me."
"Perhaps you have heard of the event known as Earthfall on your world? Even here the fragments of the Starstone had an effect. One landed here and absorbed the energies of the Dreamlands and began to change the planar properties of this realm. When people would dream, whatever they experienced here would take effect on them in the waking world also. Many died or lost their sanity. Entities from this realm would latch onto the dreamers' minds and follow them back into the waking world causing untold chaos. This went on for a time before the Dreamstone was clandestinely removed from the Dimension of Dreams and secretly sealed away in a location which was unknown until now. The recent events of Rovagug and his followers broke the strong magical barriers sealing the Dreamstone in your world in the city of Illya. Should the Dreamstone be left unchecked, its power will consume both our worlds."
Spoiler: KnowledgeQuinn recalls an obscure reference to the name Mog-Lathar, something to do with a supposed secret sect of Desna worshipers. It was a monstrous spider from an unknown plane called Leng, and led an assault against the Desnans, but was ultimately defeated. Wherever Quinn heard this from he most likely would have dismissed it as some distorted myth until now, as there was no other supporting evidence or legends about it.
As for Earthfall, I do sometimes make reference to aspects of the Golarion. Illya, the Imperial City is roughly the equivalent of Absalom, and this adventure is sort of a standalone sequel to a campaign I ran years ago that brandnewb was part of, hence the background story of the Chaos War and itís factions, etc. Earthfall would be a commonly known historic event in this setting.
Spoiler: JoeThe High-Priest inclines his head,"These things I can grant you. When my servant finds you, go with him. He will bring you to me, and I will empower you."