This means a lot to me, since I'm a DM. I really like that the guessing game of "too strong or too weak" is gone the way of THAC0. The ability to quickly calibrate the difficulty of an encounter give me a lot more time to work on the cool stuff - creating interesting encounter locations, memorable NPC's, interesting lore and great story.
In this series of posts, I'm going to go over my process for creating an adventure for a group of 4-5 1st level PCs, taking them to second level. Ideally, this will help novice or inexperienced DM's with the mechanics of adventure creation, as well as giving everyone else some neat campaign idea. I'll try to post encounter maps and stat blocks for everything. If people want to use the adventure, please feel free.
Step 1: Inspiration
The inspiration for this adventure came from a very vivid image I had in my head of a tower on a steep cliff with a cresent-moon shaped roof. The tower is set on a ridge, with a cliff behind it. The ridge is wooded, and at the bottom of the ridge a sheer chasm falls away. At the edge of the chasm is a bridge, with a small keep made up of two small round towers guarding one end.
One of the characters in the game is a priestess of Sehanine, the elven goddess of night and the moon, so I decided that the tower was a place holy to Sehanine - not a temple, though. It's a monastery, where a seer of the goddess lives. I decided to call it the Sanctuary of the Waning Moon.
Step 2: Antagonists
I'm going to crib the basic idea for the villain of this piece from the second book of Peter Morwood's amazing series about Aldric Talvalin, called The Demon Lord. The entire series is 4 books, the Horse Lord, the Demon Lord, the Dragon Lord and The Warlord's Domain. If you can find them, they're a great series. The antagonist here is a demon-god, called Ithaqua - previously a god of harvest and growth, the disappearance of its worshippers has caused it to degenerate into a demon representing rot, blight and corruption. I'm not going to put the PC's up against the demon here, just have them investigate a symptom of it's corrupting influence - in this case, a seer of Sehanine who has been possessed and driven mad.
Since Sehanine is an elven goddess, and the demon is a nature-related one, I'm going to have links to the Feywild scattered throughout the early adventures, with the idea that the PC's will eventually have to go there to stop the demon, ideally at around 10th level, but that's further down the road.
So the basic plan here is to have the PC's sent to investigate the Sanctuary of the Waning Moon, to find out why the seeress there has not communicated with the regional temple in some time.