I'm running it now and had to do lots of prepwork and research to get to where I'm comfortable. Here are some great resources I used:
Reddit Discussion (
https://www.reddit.com/r/dndnext/comments/36vwdy/princes_of_the_apocalypse_resources/)- Lots of great links. The top comment has a link to a Google Drive folder with a Campaign Outline I found very helpful, PotA Suggestions document which I've followed closely, and another document distilling the cult information for easy reference. Solid gold
A Guide to Princes of the Apocalypse (
http://thecampaign20xx.blogspot.com/2015/04/elemental-evil-guide-to-princes-of.html) - lots of great links and info
PotA Flowchart (
https://www.reddit.com/r/DnD/comments/36unfa/5e_spoiler_princes_of_the_apocalypse_flowchart/) - Also good to visualize. Look down for the colorized one
I found the adventure as written to be a little bit... static. The outposts are just there, the cults hate each other for no good reason, and nobody's doing anything. It's a snapshot, not a plan in motion. So I made a few changes for my own campaign and I think they've been working well:
• I moved the four cult outposts into a nice diamond pattern, with Feathergale Spire on the south, Rivergard Keep on the east, Sacred Stone Monastery on the north, and Scarlet Moon Hall on the west.
• There are no longer direct links from the outposts into the dungeon. Instead, I positioned the ancient ruins of Tyar-Besil in the center of the diamond in a valley filled with natural geothermal features (mixing air, fire, water, and earth!). The above-ground ruins are lightly guarded. There's a main passageway that leads into the Temple of Black Earth, but in the same complex are entrances into other parts of the dungeon -- a river, a hollow lava tube, and a "back door" into the dwarven redoubt under the city (remember, the Besilmer dwarves experimented with above-ground living, so the underground complex was more of a backup).
• I have the cults working together instead of working against each other. This makes them feel like more of a threat. They're all one cult, the Cult of Elemental Evil, and each element has its own sect. There is some friction between the cults which clever players can use to drive a wedge into their social order.
• I have the mysterious drow figure who created the four weapons as the actual cult leader, with the prophets right under him. He's an ancient lich from the days when this complex was a drow city that worshipped Ghaunadar/Tharizdun/The Elder Elemental Eye and he's been working a long time to bring this to pass.
• Just as the characters get involved, the cult is completing its next step toward summoning Tharizdun. Each outpost (Feathergale Spire, etc.) sacrificed 12 commoners in a ritual to open an "Elemental Rift" at each location. The means of sacrifice was specific to each location (drowning, hanging, crushing, burning). Now that the rifts are open, the next step in the "Fourfold Rite" can commence, eventually leading to the arrival of the Princes, then Tharizdun himself. Too bad the heroes showed up at this moment...
• The last major change I made was tying the missing delegation in better. Using Grumink the Renegade, I had a dwarven sympathizer planted in Mirabar trying to access the old forgotten tomes containing the Fourfold Rite. He managed to convince the head librarian that the library at Waterdeep requested an exchange, so they brought the book, along with a bunch of related ones, on the journey to Waterdeep. Along the way he convinced them to detour, at which time the planned ambush happened. Grumink was handsomely rewarded, and the cult now had the full text of the ritual they need.
These things have added a sense of cohesion and urgency. The heroes can't just take their time, because
is happening. There's not even any time to journey down to Waterdeep to let someone know what's going on. The heroes need to disrupt the Fourfold Rite and fast. If they don't act, the world will be plunged into hell in a couple of weeks as the Princes emerge from the Nodes and call forth their father, Tharizdun, to reshape Faerûn as a plane of elemental chaos!
In the last session my players defeated Aerisi then hustled to the Fire Temple and killed Vanifer before she could do much. All three prophets "felt" Aerisi's death and were making plans. At the moment, Vanifer was gathering her things to head down to the Fane. She never made it. Then the heroes hid so they could rest a while. I wasn't going to introduce inter-sect squabbles, but I spontaneously decided that some minor disagreements had begun to weaken the cohesion of the sects with each other, then Tharizdun declared that they had to determine which among them was the strongest. Killing Aerisi broke the balance of power. When the heroes emerged from their hiding place, they found they'd missed several hours of brutal sectarian warfare, and the hallways were littered with dead cultists from all sects. They're about to pursue Marlos into the Fane. Most likely they'll find him there, which means it's looking like Water will be their Node. Too bad; I really liked the Weeping Colossus. Ah, well. They still need to throw the four weapons into the Nodes to seal them.
