Here's the end result: link
That shouldn't have taken so long, but it took me a while to sort out something for the warded rooms of the genius loci.
As is quite evident from looking at the PDF, I didn't end up making any maps for this one. I don't believe any of the places would've really benefited from the effort. I know there are modules out there that love to map out every last space where something might happen, but as I'd said back when I was talking about urban campaigns and also with my random "village with a cult" generator, I don't see much point in making maps if they aren't going to be more useful than improvising something on the spot.
Since this was a pretty simple adventure to scale up or down, I decided to aim it at mid-level play, which I'd consider to be about levels 3 through 6 in old school D&D. Admittedly, this isn't an adventure where levels would play too much of a factor, but that range lets me get away with decent-sized squads of Dirge members for the initial kidnapping and escalated reactions to interference, and it also lets me be a little more comfortable with unclear puzzles since the characters are more likely to have access to some degree of utility support, whether in the form of magic or NPC allies.
Speaking of puzzles, I was sure from the beginning that I wanted to have a "direct" way of sealing the genius loci but a more complicated way of confronting it permanently. Initially, I had a color using acronyms and color codes, but I ditched that for a few reasons.
Primarily, that didn't really have much of anything to do with the rest of the adventure, so it felt like a swerve for no good reason as soon as I wrote it down. While I've got no objections to having some variety in the challenges that the players are presented with, there's a difference between variety that has some degree of sense and variety that's just throwing random shit together to see what you get.
Secondly, I wanted the puzzle to be something that a random person could conceivably solve, in order to hint at the order's origin. The first design ended up feeling too much like something that would've been almost impossible to solve without having the clues I put in to the solution, which themselves wouldn't have existed prior to the order, thus ending up in a senseless paradox.
Finally, I tend to dislike puzzles that rely on English language tricks, unless the setting is explicitly meant to be the real world. This is probably more of a personal hang-up, but I just dislike limiting myself by forcing a specific real language to be used in a fantasy setting.
Well, I suppose there's also a fourth reason: I feel like I'm bad at making riddles, so once the thought crossed my mind, I wanted to run with it for some practice. One of them is ripped almost straight out of -C's "Tricks, Empty Rooms, & Basic Trap Design" PDF, and I used his advice on making riddles to come up with the other two. Having a riddle room is still a bit of a curveball, but at least the topics do relate to the central motifs from the rest of the adventure.
It should go without saying (thus I didn't write it in the PDF), but as ever with those types of riddles, the GM should try not to be a total asshole about needing a strictly-worded answer.
As far as treasure goes, I'm not a huge fan of packing more or less all of it into a single area, but I didn't think I could spread it out more without distraction from the main thrust of the adventure itself. In campaign play, I'd certainly be willing to flesh out the node locations more, and I could see including more opportunities for treasure in Centia's manor or the Hermina family mausoleum, but for brevity's sake, I didn't go into such details here. The adventure as a whole felt like a pretty brief one, so I figured a total haul that could roughly get four 4th-level fighters up a level (and thus an expectation that the actual treasure earned would be around half of that) was a reasonable target, hence a total treasure value of 34,700 sp (vs. the rule-of-thumb target of 36,000).
All in all, this feels like a nice little adventure, suitable for a one-shot session or as some side content in a longer campaign. I'm not as excited about it as I was for the Walled Mound of the Hive Caller, but it's something that I could definitely see myself having a fun time of running. Let me know how it works for you, if you decide to use it!