The party pursued the drow deep into what appears to be a section of the underdark. A long consistently sized hole bored deep into the ground, at times passing through other diverging chambers leading into different biomes and areas. On the 9th day of travel the party passed through an area with an underground river and various diapson crystal deposits. There they decided to throw a rock at one of the crystal formations. It turned out to be an orange colored formation of diapson. The crystals exploded and alerted a nearby rearguard force of drow that had seemingly been left behind as sentries.
Dispatching the drow, the party took a bit to harvest some of the crystals, gathering some necromancy, abjuration, and evocation crystals. During their harvest, they noticed that all of the crystals were oriented in the same way, pointing away from a central location as if manipulated by unseen magnetic forces. All of the crystals pulse with a slow, but study rhythmn.
Moving onward from the crystal cave, the party traveled another half day or so before reaching a large chamber dominated by a bioluminescent formation that gave light to the large chamber and seemed to fuel the growth of a large underground forest. Tilia, using her spiderclimb abilities, made her way around the sheer rock face, picking up thetrail and tracking the footprints to the west on the other side. There she found a rope bridge spanning the underground river. The footfalls in the area showed heavy traffic, mostly east and westward. Looking westward, Tilia found ladders leading to a lower part of the underground forest. Estimating numbers at least dozens if not more feet had traveled back and forth this way. Tilia found a nearby boat moared on the shore and was able to bring the rest of the party over.
Following the original tracks to the west, the party continued onward for about an hour before coming upon a large dome-shaped chamber with a massive jet-black ziggurat temple. The temple sits in the middle of the chamber with a large beacon of light emerging from the top and entering into a large brightly lit spherical object. Around the temple there seems to be a moat of undead bodies that swim over one another clawing and reaching up in eternal agony for any living that might fall down below.