Well well well, look what the shoggoth dragged in.

My Arden Vul campaign, 6 months in

I’ve been running a campaign of The Halls of Arden Vul for 6 months now. It’s been a lot of fun so far, and we have barely scratched the surface: we’ll be playing this for a long time yet. I do not regret the expensive books at all.

This post is for the potential Arden Vul GM, still on the fence over whether to run it or not. I’ll cover what it is and generally how I feel about it now that I’ve got some experience with it (though this isn’t a comprehensive review); the highlights of my campaign and what crazy stuff the players have got up to in the last 24 weekly sessions; and then the practical matters of what rules I use (including my house rules), what I prepared before starting the campaign, and how I run it week to week; and finally I’ll end with some assorted advice.

If you’re completely unfamiliar with Arden Vul, I highly recommend the 3d6 Down The Line actual play. They’re now 50 sessions in and unlike many actual plays they focus on playing the game as you would normally play it at home, rather than being a performance to entertain the viewers. Of course, there’s still some of that, but it is much more like a normal game than most. It’s what put Arden Vul on my radar and ultimately convinced me to get it.

This post has a lot of spoilers. So if you’re a player (including my players), turn back now.

What is Arden Vul?

Arden Vul is a megadungeon—that is, a single dungeon large enough to be the site for a whole campaign, supporting months or even years of play—there’s an appendix with information about the wider world too, but that’s really just providing context for the material in the dungeon.

I actually think the introduction from the book does an excellent job of selling it, and is what I sent my players when I pitched Arden Vul to them:

Who has not heard rumors of the lost city of Arden Vul? During the glory days of the Archontean Empire, now 1,200 years in the past, Arden Vul was a small, but important, wealthy and secretive imperial center located atop a 1,500’-tall cliff at the head of Burdock’s Valley. Dominated by the imperial administration itself, as well as by the great temples of Thoth and Set, the city attracted alchemists, scholars, priests and sorcerers by the droves. Seeking the lost secrets of long-dead civilizations as well as the mysterious element known as arcanum, the Archonteans delved deeply—and secretively—within the mountain. Alas! The terrible civil war that rent the Archontean Empire, that is, the war of Sortians and Theosophs, led to the utter destruction of the city and the withdrawal of the imperial legions from the western continent of Irthuin.

Now, with the renaissance of imperial power, it is possible for well-equipped adventurers to make the long trek to Arden Vul from the exarchates of the coast. Tales of gold piled in imperial vaults, legendary magical artifacts resting in unspoiled crypts, and the fruits of the lost secrets of ancient imperial smiths and mages lying ripe for the picking are legion. Yet alongside the tales of lost treasures are other, more unsettling whispers. How could a lost city remain unplundered for more than a millennium? Surely only the existence of the cruelest of foes and unimaginable evil within the mountain can explain Arden Vul’s unspoiled status. Only the bravest, the cleverest, and the luckiest of adventurers will survive to plumb the mysteries of Arden Vul.

I described it to my players as a dungeon with history. This is the first megadungeon our group has played, so I really wanted to emphasise that this isn’t like what we’ve done before. Arden Vul isn’t an “adventure site.” You can’t “clear” Arden Vul. It’s a place to explore, full of ancient mysteries to figure out, lost treasures to recover, and denizens to bargain with.

There’s no overarching story. Or, rather, the book presents several possibilities for that. But the default mode of play is completely player-driven.

The setting is a kind of Ancient Egypt / Rome / Byzantine Empire mashup. Not exactly your standard fantasy setting, but close enough that it’s not really a problem. There’s also a strong sci-fi element, but that’s hidden away from the players initially. Mine haven’t stumbled upon it yet (but I want them to, so much).

The material is dense. Arden Vul may have nearly 2000 keyed rooms (and countless unkeyed corridors), spread across 10 main dungeon levels and 13 sublevels, but it’s not just a load of empty rooms and uninteresting spaces. More often than not, rooms have something interesting in them, something to steal, experiment with, or talk to. Even the very construction style gives clues to the dungeon’s secrets, with different inhabitants building their rooms at different times and in different ways, and later inhabitants repurposing them but leaving the stonework intact.

Again, I highly recommend you check out the 3d6 Down The Line actual play if you’re not familiar with Arden Vul at all.

Is it fun?

Emphatically, yes. It is so much fun.

I’ve gushed to my players between sessions a few times about what I really love about Arden Vul: everything is interconnected, and the interesting stuff isn’t gated behind being deep in the dungeon.

Firstly, connections. There are passages and level connections everywhere. A couple of entrances to the dungeon are fairly well-known, but there are also hidden ones which—if you can find them—will bring you really deep into the dungeon really quickly. Every dungeon level has passages to multiple other levels, so once you’re inside you can get around pretty quickly as well. Some passages are easier to find, and so fairly well known to the adventuring community; others are less well known (or even totally unknown) and so knowing where they are gives you some advantage, and possibly leads you to some undiscovered treasure. But that advantage comes with risk, because the less well known (and less well-travelled) parts of the dungeon are more likely to have unknown dangers!

Secondly, interesting stuff. The very first thing you encounter in the ruined city on the surface is the Obelisk of the Sun. That, along with the Obelisks of the Moon and Stars, lead to the buried bridge of an ancient alien spaceship if you can solve the riddle and find the keys, which you can do entirely on the surface without setting foot into the dungeon. It’s easier if you go deep into the dungeon and find some useful lore and possibly some keys, but you can do it without that. And the whole dungeon is full of this sort of thing. Secrets upon secrets that delving into the dungeon helps with, but isn’t required. You can find something interesting in Arden Vul and just start working away at it, unlike some dungeons where you can’t really make progress beyond a certain point without being high level.

I’ve read the books, so I know the whole truth. But I can’t predict how the players will experience that truth, and listening to them try to puzzle things out from the scraps of lore they’ve managed to uncover so far is really enjoyable.

Looking back through my notes, this line near the beginning of the campaign catches my eye:

So far the players have been under the impression that Arden Vul is a dead place full of mostly unintelligent monsters. But it’s about to get weird.

This was just after they found a route down to the uppermost Troll Lift station on level 5, and we ended the session with them en route to the Arena level.

That’s another thing I like about Arden Vul: it’s not just a dungeon. There are intelligent monsters, there are factions, there’s a whole subterranean society. Exploring dusty old rooms and figuring out ancient mysteries is fun, but being able to interact with people is fun too, and keeps things fresh. The current inhabitants are tied into the dungeon history, too, and learning about one teaches you about the other.

However, it would be remiss of me to portray it as all sunshine and rainbows. Running Arden Vul does have some challenges.

The main problem is that it’s just not as well laid-out as some other OSR material, such as the OSE books and adventures. Descriptions tend to be long and wordy, and the PDF isn’t hyperlinked, which makes skimming through things at the table a little tricky at times. I did a lot of reading before starting the campaign, and still sometimes have to call a short break while I look something up.

I’ll go into how I prep and run sessions more below.

It’s not a module you can pick up and run with no prior work, unlike some dungeons, but despite that I still highly recommend it.

My campaign (so far)

We play weekly on Sundays for 3 hours and have had a couple of short breaks to do one-shots of other systems. Including session 0, we’ve played 24 sessions of Arden Vul now.

The players have explored about half of level 1 (The Basement), a third of level 2 (The Howling Caves), a fifth of level 3 (The Halls of Thoth), and small fragments of level 5 (The Obsidian Gates), level 6 (The Troll Lifts), sublevel 4 (The Goblin Warrens), and sublevel 15 (The Druid’s Retreat).

They’ve met the Halflings, the Varumani (only in neutral spaces like the lifts), and the Beastmen, seen at a distance the Goblins, and heard rumours of the Heqeti (only as a historical foe), Kerbog Khan (or at least, one of his automatons), and the Set Cult.

I try to get the players to be somewhat goal-oriented, but it never lasts for more than a session or two. So they have a lot of open threads, but broadly their major priorities right now are:

  • To explore level 2 while the baboons are still afraid of them.
  • To get a full set of glass teleportation squares.
  • To find the Obelisk of the Stars and get two more ankh-keys.

My priority is just to have them find cool stuff, as there is so much cool stuff in this dungeon, and the point of a cool secret is to be found.

Meet the party:

  • Fern Thistlefoot, Halfling 3, PC
  • Cinnabar, Dwarf 4, PC
  • Ethelflad, Acolyte 4, retainer
  • Periclase, Dwarf 4, PC
  • Ari, Fighter 3, retainer
  • Esme, Thief 3, retainer
  • Tubcleaner, Goblin 3, retainer
  • Tresti Iredell, Magic-User 2, retainer

We’ve somehow not had any PC deaths yet, but we have had a few retire, and we’ve had many retainer deaths.

  • Calsif, Paladin 1, PC: retired due to the player leaving
  • Aesgeir, Mage 1, retainer: the same
  • Agnar, Thief 1, retainer: killed by chasm cephalopods on level 3
  • Chyde, classless, retainer: killed by ghouls on level 3
  • Decima, Thief 1, retainer: died with Chyde
  • Rodger, Fighter 1, retainer: retired after a big payday
  • Shane, Mage 3, PC: retired due to the player wanting a different class
  • Hilda, Magic-User 1, retainer: killed by a wight on the surface
  • Nayan, classless, retainer: died with Hilda

The players like to travel back to Gosterwick after every big haul to deposit their loot in the bank, level up, and spend a few days resting. They also favour short delves. So quite a lot of time has passed in our 24 sessions: the campaign started on the 24th of Fidios (December), 2993 AEP and it’s now the 11th of Lucrios (April), 2994 AEP.

I’m not going to give a complete blow-by-blow history of the campaign, but here is a rough outline, along with a little of my thinking (where I can remember it):

  • 24-Fid-2993: Our campaign begins with the PCs standing at the base of the Long Stair, next to the deafeningly loud waterfall, drenched in spray and looking up the 1500ft cliff. They ascended, looked at a few things on the surface, and were guided to the Sign of the Broken Head by the watchmen.

    I was afraid that we might have had a TPK in the first session, as they almost crossed the bridge into the donjon, which is guarded by constructs. I narrowly avoided that by having them hear the watchmen in the towers yelling to get their attention.

  • 25-Fid-2993: The first delve. The party figured out how to open the hidden door in the Pyramid of Thoth that leads down into the dungeon, and descended.

    Manipulating the statue of Thoth in the wrong way can open a second door that leads to a trap. I decided that wasn’t very fun, so I removed that.

    They met Roskelly and the rest of the halfling gang, grudgingly paid for an “adventuring licence,” and found a secret stairway up (3-27). On the way out, they wrote “Roskelly is a bitch” on the stairwell walls.

  • 27-Fid-2993: Our first use of the Death & Dismemberment house rules: Cinnabar got concussed by zombies and needed to spend several days resting. The other party members left her behind at the Sign of the Broken Head and continued exploring the surface, which felt safer than going into the depths, and found the Sodality of the Fist’s secret entrance (AV-12). The players were really keen to see if this brings them down into the dungeon without needing to pass the halfling checkpoint.

  • 29-Fid-2993 to 12-Mol-2994: The party sold a statue to some merchants at the Sign of the Broken Head. Unfortunately, payment is upon delivery to the town of Newmarket. So the PCs spent a few weeks lugging it down to Gosterwick and then transporting it via mule caravan to Newmarket. 5000gp never felt so sweet.

  • 13-Mol-2994: Ethelflad found a cool stone torch. Unfortunately, it fused itself to his hand, and he couldn’t give it up or let it down. The party left the dungeon after sunset, and had their first run-in with Craastonistorex, a dragon living in the ruined city, who extorted half their treasure from them.

    By some incredible fluke, every single random encounter I’ve rolled on the surface has been with Craastonistorex! I’ve altered all of them since, as I don’t want the players to feel like the dragon is stalking them…

  • 14-Mol-2994: The party don’t want to risk messing around with curses, so they went to Gosterwick and made a large “donation” to one of the temples to regain the freedom of Ethelflad’s hand.

    There are no prices listed for clerical services in Gosterwick, so I took the costs at The Sign of the Broken Head and halved them. I also decided the temples wouldn’t blatantly put it in terms of selling divine magic, even though that’s what’s happening.

  • 15-Mol-2994: They descended the staircase at AV-12, spotted a secret door in the room they arrived in (3-52A), opened that—revealing another staircase—and continued down

    Now on the 5th floor, they met a troll who proclaimed himself to be “Riglon, Vice-Overseer of the Lifts, Appointed by the Thegn” and demanded their obeisance. Riglon oversees a rickety basket contraption mounted to the side of the chasm, he says the party can ride it down if they pay a fee. Of course they do.

    The book says that the normal fee is 10sp per person, but that Riglon will charge them 1gp. In the session I didn’t really pick up on how weird a statement that is (since 10sp = 1gp), but I looked into it afterwards and found that in AD&D, 1gp = 20sp. So Riglon (and most of the other lift operators) charge unsuspecting rubes twice the normal price.

    I decided to leave it, and also to not adjust any of the other prices in the book. Everything is cheaper, but treasure is also worth less, so it probably works out fine except in the odd case, such as this.

    They arrived on a floating island, now about 1200ft down, and met another troll—Hakrim, Vice-Overseer of the Lifts—who told them that the arena and the inn are to the north-east, and some sort of Archontean shrine complex to the south-west. The party went to the arena, arriving just as a fight began, and saw a crowd composed of all sorts of races: humans, goblins, trolls, and strange beast-headed men. They also saw at a distance the Lord of the Arena: a tall bipedal humanoid with two little horns, wearing strange clothes; not a race they’re familiar with.

    Pondering what this all means, that evidently a vibrant society dwells in the halls, the party retired to the inn and paid some exorbitant prices.

  • 16-Mol-2994: The party went to check out that Archontean shrine complex, and discovered a shrine dedicated to the famed archon, Marius Tricotor, who subjugated the trolls and conquered the halls! Periclase spotted a secret door in the ceiling and improvised a rope contraption to get up there, discovering a passage north.

    The passage led, indirectly, to the lost tomb of Marius Tricotor (and to some undead guardians the players managed to sneak around), which the party looted with that innate knack for hidden treasure that players have, finding a lot of wealth, a Vorpal Sword, and a Rod of Lordly Might.

    The Rod of Lordly Might is a bit of a game-changer as it can turn into a flaming sword without consuming any charges. So it has dramatically changed the lighting situation. While it’s led to a lot of cool things, I slightly regret that I made light nearly a solved problem so early in the campaign. Though, torches aren’t entirely useless: sometimes having a second light source is handy, as is being able to hide that you have a flaming sword.

    In hindsight, I made it far too easy to sneak around the guardians.

  • 18-Mol-2994 to 03-Deut-2994: The party returned to Gosterwick, sold or banked all their treasure (transforming immediately from small-time customers of the Rarities Factor to some of its most significant), and all reached level 2. They decided to stay for a while longer to squander some of their new-found wealth on philanthropic ventures, gaining additional XP, and all reaching level 3.

    In this time Agnar, the first thief, was hired. It would not be for very long.

  • 05-Deut-2994: The party descended back into the dungeon and thoroughly explored the area around 3-52A. They discovered the Great Seat of Contemplation, getting a glimpse of all the chasm-connected rooms on level 3. They also noticed that the strange glyphs on the Seat look somewhat similar to (but more sophisticated than) some engravings on statues outside the arena, but it’s not a language any of them recognise.

    I’m pretty sure the players have since forgotten what they saw.

  • 08-Deut-2994: The party managed to string up a rope bridge across the chasm (by lobbing a grappling hook at the Lesser Seat of Contemplation), and explored beyond, hoping to join their level 3 map segments.

    Chasm cephalopods killed Agnar. The rest of the party barely made it away alive. Cinnabar got poisoned by giant centipedes on the way out and needed to spend a few days resting.

  • 19-Deut-2994: With everyone healed, and a new thief—Decima—in tow, the party returned to the dungeon.

    Decima picked a lock, the first successful use of thief skills in the campaign, and then promptly got killed (along with Chyde) by the ghouls on the other side of the door. Everyone else narrowly escaped, again, unable to recover the bodies or equipment.

    While fleeing, the party encountered a friendly ghost, who couldn’t speak but who pantomimes to them that he is unable to rest due to the ghouls which disrupted his burial.

  • 27-Deut-2994: Periclase found some weirdly well-preserved, and incredibly comfortable-looking, boots on the feet of a dwarven corpse. He immediately put on the cursed footwear. They also found a dwarven life-stone of the Malachite clan, and decide to send that back to Kazildor, city of the dwarves, when they can.

  • 28-Deut-2994: Armed with spears and tactics, the party made use of a chokepoint to thin out the ghouls, then advanced into the desecrated burial chamber of the Priors of Thoth to put down the remaining few and their wight leader. They then put the bones of Jacobus, the ghost they met previously, into his tomb. Jacobus appeared, thanked them, and indicated a secret compartment full of more treasure than could be carried out in one trip.

    On their way out the party were discovered and chased by a patrol of beastmen, who warned the party away from this area of the halls and cut down the rope bridge.

    The players also lied to the beastmen patrol, saying that the halflings sent them this way. I totally forgot about that, so nothing came of it.

  • 29-Deut-2994 to 10-Tot-2994: Defying the beastmen, the party retrieved all the loot (with a couple of trips), spent a while getting this (and previous) loot identified, Periclase has his cursed boots removed, and Cinnabar arranges for some dwarven adventurers to take the life-stone the party found back to Kazildor.

    One of the magic items they found was a Belt of Giant Strength. Periclase decides to wear it, and the player rolls the best possible stats: +6 to hit, +12 damage. Periclase also has the Rod of Lordly Might, but is only level 4 at this point, so is a bit of a glass cannon.

  • 11-Tot-2994: The party spend the day reading a book they retrieved, The Book of Priors, which details numerous obvious and hidden stairwells in the halls which the party wasn’t previously aware of.

    I spent some time before this session thinking about what stairwells the book might describe, and how it would describe them. I came up with this list of clues:

    • south of the entrance to the catacombs, west of the Hall of Judges, north of the Glory of Thoth beneath the pyramid

    • due east from Thoth the Knower of Secrets at the north end of the chasm

    • near there, beyond a hidden door in the southern wall of the Room of the Ibis Guardians

    • beyond a secret door east of the Greater Hall of Columns, where the corridor turns north to the Lesser Seat of Contemplation

    • west of our glorious Temple of Thoth lies the Temple of Set, and west of that are stairs down to the Halls of Set

    • the residence of the Overseer of Truth is up the great spiral staircase to the south-west of the Great Hall

    • north of the bridge across the chasm on the level of the Obsidian Gates, there is a stair down warded by statues of legendary heroes

    • north-east of the Tomb of Marius Tricotor, a stair down to the administrative complex

    • at the northern end of the administrative complex, a spiral stair down to the clerical offices near the Court of the Troll Thegn

    • the clerical offices north-west of the Court of the Troll Thegn have a passage to Marius’ outpost at the floor of the chasm

  • 12-Tot-2994: Following directions from the book, the party found a secret stairwell choked with cobwebs. Unfortunately, they’re driven back by spiders—but throw a flaming torch into the webs as they flee.

    They’ve not gone back here yet. Another unresolved thread…

  • 13-Tot-2994: The party went up the secret staircase they found way back in their first delve (3-27) and discovered level 1 of the dungeon. They met Lankios, refused his disgusting soup, and found the exit to the surface. But rather than leaving, they went back down to level 3 and out through the Pyramid of Thoth, to avoid tipping the halflings off that there’s another way out.

    There was much rejoicing over finding an entrance to level 3 not inside the territory of another faction.

  • 14-Tot-2994: The party decided to search the surface some more, and found the stairwell down to the goblin warrens (AV-16). Listening at the Lesser Obsidian Gates and hearing many goblins, the party decided to not open them. But they make note of how deep they are and start thinking about how they might find the other side of those doors (and whatever goblin town is there) from inside the dungeon.

  • 19-Tot-2994: The party visited the House of the Thesmothete to incorporate as a legal entity, A Short Adventure, so they can own property in Gosterwick jointly. They also bought some land and arranged for the construction of a small house.

    I wasn’t sure how much to charge them for land, so I somewhat arbitrarily settled on 10gp per 5ft square (half that for citizens), with a 5% annual property tax. I looked through a lot of blogs and books, and was surprised that I couldn’t find anything more official for buying land in a settlement.

  • 22-Tot-2994: The party decoded another clue from the Book of Priors and found the route up from the catacombs of level 3 to level 2. They then break into Isocritis’s lab, destroy his animated statue, and abscond with his treasure. On the way out they fight Sisko and a bunch of baboons, nearly killing Sisko in the process.

    I decided that once Gerrilad learned of this, he’d go fully paranoid, assume another dungeon faction had hired the PCs to steal something, and start preparing an ambush for if they returned.

  • 28-Tot-2994: The party met with the Thesmothete about building a free hospital in Gosterwick. They fully funded its construction and one year of operating costs up front.

    I introduced the “institution” rules from Downtime in Zyan for this. The players had been talking about setting up a temple or a hospital or something for a while, and I wanted it to be an ongoing thing, not just something they pay money for and never interact with again.

  • 30-Tot-2994: The party tried plugging a large silver ankh they found in Isocritis’s lab into the Obelisk of the Sun at noon. Nothing happened, but it fits so well…

    They searched the surface some more, and found the Obelisk of the Moon. The players immediately jumped to the conclusion that there must also be an Obelisk of the Stars, and started pouring over their map to try to work out where that could be.

    “We’re gonna need more ankhs” – one player

    They then entered the Long House, and we nearly had a TPK. A Potion of Control Undead (Ghouls) that they previously found saved the day, though Hilda and Nayan are killed, and Esme gets level-drained.

  • 03-Luc-2994: The party returned to level 2, to be ambushed by the baboons Gerrilad left waiting for them. They managed to escape into a room and spike it shut, but the baboons start to break the door down.

    We ended the session on that cliffhanger. I worked out a timeline for how long it’d take one baboon to alert Sisko and Trefko, who’d go alert Gerrilad, and then gather some reinforcements. I decided that Gerrilad would wait in 2-35 and call for Isocritis (then in the library), whereas Sisko and Trefko would try to capture the PCs (maybe killing some) and bring them to Gerrilad.

    The party took up defensive positions, doused the floor in front of the door with Oil of Slipperiness, and waited for the door to burst open. They then managed to drive off the baboons, though Sisko and Trefko fled when they saw their minions being cut down.

    They then cautiously explored the floor, and found Gerrilad in the middle of torturing Gwelf for information, as he’d assumed that the dwarf PCs were connected to Gwelf. Periclase assumed Gerrilad must be some sort of spellcaster, and used a Potion of Flying, a Ring of Friendly Defense (to turn invisible), and his Rod of Lordly Might (in axe form) to sneak up to Gerrilad and behead him.

    I was so proud.

    I decided that since an axe isn’t really a finesse weapon, the player could choose between a guaranteed hit (but having to roll for damage) or needing to roll to hit (but having a guaranteed kill). The player went for the latter.

    The players then freed the prisoners and Jost led them out through the secret passage just north of 2-35 (leading ultimately to the stairwell in 2-46).

  • 04-Luc-2994: The party returned to Gosterwick to deal with some treasure, buy a mule, and arrange for Creon (of Creon’s Curios, the pawn shop) to keep an eye out for any little glass teleportation squares.

    Clever thinking, paying the pawnbroker to keep an eye out for specific items for you. I decided that there’s a 1-in-10 chance per week that Creon gets a glass square, and if he does it’ll be a random colour that the players don’t already have.

  • 10-Luc-2994: The party returned to level 2, with Tresti to seek out Isocritis and retrieve her spellbook. They found signs of some sort of clash near the library: a row of baboon heads and spiked-shut doors marking off a section of the level. There was also a note on the library door, to “the adventurers,” from Isocritis, saying he was willing to negotiate—just knock, step back 20ft, and do not call out.

    After a lengthy discussion, the players decided to give it a try, and found Isocritis surprisingly agreeable: he was willing to give up Tresti’s spellbook, all he wanted was for himself and this little part of level 2 to be left alone.

    In hindsight, I should have realised the players would interpret those instructions as a trap. But Isocritis isn’t a fool: he just wanted a little space between himself and the party, for his zombie baboons to stand in as a defensive line, in case negotiations went poorly.


We use the OSE Advanced Fantasy rules. Arden Vul is written for AD&D, so I also reference OSRIC for AD&D-specific material. Fortunately, OSRIC is free. The main things to convert are:

  • Alignment: B/X D&D uses one-axis alignment, AD&D uses two-axis.

    My general approach is to treat Good and Evil as personality traits, not as alignments. To say someone is “Good” or “Evil” is just a descriptor of how they tend to act, nothing more. Whereas Law and Chaos are more connected to your religious beliefs and which gods religious characters are pledged to. I handle magical effects which key off alignment on a case-by-case basis.

  • Monsters: Where monsters have an OSE version, I use that; otherwise I use the Arden Vul version without further conversion.

    As AD&D is a bit higher-powered, this means the AD&D monsters are a bit stronger and more resilient than the OSE ones. But that’s not really been an issue so far. The players just have to be cautious.

  • Magic Items and Spells: A lot of these aren’t in the OSE Referee’s Tome.

    Unfortunately, AD&D spells don’t quite map cleanly to OSE, because in AD&D one combat round is 60s, and what B/X D&D calls a “round”, AD&D calls a “segment”. I don’t like specifying spell durations in “minutes”, since nothing else in the game uses that, so when I copy a spell over from OSRIC I pick a new duration for it.

I mostly convert things on the fly, I don’t tend to read ahead and pre-convert things. This does mean that things might change between sessions, but I’m open with the players about it, and it’s fine. I told them going in that we’re playing a different system to the one the material is written for, so I would be converting it on the fly and might make mistakes.

My collection of House Rules is pretty standard, I think. No major surprises there.

It’s not a complete document in itself: I’m incorporating some material from the Carcass Crawler zines and from Downtime in Zyan. I do toy with the idea of writing and printing a complete book that’s the subset of the OSE rules we’re actually using, plus all the house rules; but then I wouldn’t be able to distribute that, and also I change the house rules on occasion so it’d get out of date.

Maybe something for the future, I could celebrate one year of Arden Vul (in another 6 months) by giving myself and all the players a custom rulebook. That’d be fun.

The house rules have been fairly static from the beginning, just with minor tweaks, other than three significant changes during the course of the campaign:

  • Carousing: Everyone knows carousing rules. Who doesn’t love a carousing mishaps table?

    We found we just didn’t really use it. The philanthropy rules come up just about every time the party return to Gosterwick, but I think we only ever went carousing once. The players just didn’t make the sort of characters who go on wild parties, accidentally burn down taverns, and wake up in the town gaol up to their eyeballs in debt. We had a discussion about what sort of fantasy carousing rules model, decided that wasn’t the game we were playing, and removed them.

  • Training: AD&D requires you to undertake training to level up, and there are trainer NPCs in Gosterwick. So when we started the campaign, we decided to use training rules.

    We ended up removing it because it was just adding a time and money cost to levelling, and wasn’t in practice encouraging the sort of gameplay I wanted it to: which was building relationships with these powerful local NPCs. That just… didn’t happen. My fault for not pushing it more, but there’s enough fun stuff going on already without needing to make those specific NPCs super relevant to the campaign.

  • Philanthropy: We started with a fairly simple “donate some gp, receive 80% as XP” rule.

    But once the players came into a lot of wealth after looting Marius Tricotor’s tomb, they started talking about maybe building a temple to Adenia Tesseron, who doesn’t have her own temple in Gosterwick, or maybe building a free hospital. That’s awesome and I want to encourage that sort of thing, but I also wanted to encourage an ongoing interaction with any organisation they establish.

    So we decided to pull in the institution rules from Downtime in Zyan.

    While I was at it, I also added an incentive to donate to a specific cause (and so interact with powerful NPCs) rather than just being generally philanthropic. And it’s working great! The players have set up a free hospital and one of them visits it to check up on things every time they’re in town.

I do want to mention, though, that we’ve just not found the Mage class fun, and it might get axed from the next version of the house rules. Your experience may vary, but the Mage player said after 3 months that they weren’t enjoying the class, had never enjoyed the class, should have said something earlier, and wanted to retire their character.

Not noticing that was a bit of a miss on my part.

Running the Halls

Tools we use

Normally I use Foundry for my RPG campaigns. But I decided not to for Arden Vul for two reasons:

  • Character Sheets: I knew I wanted to make some changes to the core rules, like using item-based encumbrance. So I’d need to change the character sheets. Foundry character sheets are defined in code, and while I am a software engineer by trade and do program things for fun, I didn’t really feel like reprogramming my VTT just to run a game.

    I already went down that route previously, with Roll20, and it led to a lot of work.

  • Mapping: The Foundry drawing tools are pretty bad. The assumption is very much that the GM provides cool maps with dynamic lighting and effects and everything all set up, and the players just move their tokens through the map. The drawing tools are for quickly sketching something small.

    But for Arden Vul, I wanted the players to do the mapping. I looked at a few Foundry modules, but none of them really fixed the issues to my satisfaction.

Now, after 6 months, our tech stack is:

  • Discord for voice chat during sessions, and text chat between sessions. I also put up an event for each session so people can indicate whether they’ll be present or not.
  • Dice Maiden (a Discord bot) for dice rolling.
  • Miro for mapping (we started with Owlbear Rodeo but it started to lag with the size of the maps).
  • Google Docs for character sheets and player notes.
  • For my own note-taking I use Obsidian, more on that below.

Miro isn’t an RPG-specific tool, it’s boring business software which I actually use at work. But it occasionally shows up in RPG circles because it’s just a very capable virtual whiteboard. 3d6 Down The Line did a video on using Miro for mapping that may be of use.

It performs well enough that we can use a single board for all of Arden Vul, which is great, because you can indicate level connections and can easily compare the layouts of different levels and work out how things are related.

See the appendix to this post for some examples of our map.

I’ve also made a blank character sheet available, which you can use as the start of your own. It has some automation, like filling in saving throws based on class, and computing your movement speed. It only has the classes we use in our campaign though.

Preparing for the campaign

I didn’t intend to start Arden Vul this year. I was planning to run a Delta Green campaign and then do Arden Vul some time after that, in 2024, but due to scheduling issues I couldn’t actually get a group together for Delta Green. I realised I needed a game that would be tolerant of players dropping in and out. Something without a big overarching linear story which you need to be aware of to meaningfully contribute.

So I picked Arden Vul.

Unfortunately, this gave me two weeks to prepare a huge campaign I’d intended to spend the best part of a year leisurely reading through. But I managed it, and so can you.

Firstly, the main thing I credit for my success was the 3d6 Down The Line actual play. This was back in May, they were 27 episodes in, and had done some significant exploration of levels 2 and 3. I felt pretty comfortable with the overarching themes of at least the upper levels of the dungeon, and I expected my players to spend a lot of time on level 3 (I was wrong), giving me time to read ahead in the 1200-page 5 book set that is Arden Vul.

Beyond that, I focussed on volume 1, cross-referencing it with volume 4:

  • General Introduction: This is gold, I carefully read all of this, and used the appendices to add context.

  • Exterior Adventure Locations: I read all of this, I could have maybe skipped some of it but it’s not that long. I read the sections on Gosterwick and The Sign of the Broken Head multiple times, as I wanted those really clear in my head as the players will interact with them a lot.

  • The Halls of Arden Vul: I read the introduction to levels 1, 2, 3, and 4 (all the ones in volume 1) to get a rough sense for what’s going on and what the layout is, and also read the descriptions of the rooms in those levels close to exterior exits. I skimmed through the rest, stopping and reading a little more closely when an interesting room name or especially long description caught my eye.

I also decided to make a small change to the dungeon at this point. The Pyramid of Thoth has a trap entrance (UP-6). I decided to just remove that, as I thought the party potentially all being killed the very first time they try to head into the dungeon wouldn’t be very fun.

After that, I felt like I had a good enough idea that I’d be able to run at least a few sessions. Of course, I’d be looking up room descriptions during play, but that’s fine, the overarching knowledge helps with quickly parsing those.

I also noted down overland travel times for places I expected them to move between frequently (like Gosterwick and The Sign of the Broken Head), the Archontean calendar, and the weather tables from Dolmenwood. See the appendix to this post for those. The travel times in particular are really useful and I’ve been adding to those as the campaign has gone on.

I then prepared for our session 0:

  • I shared the first two paragraphs of the general introduction with the players.
  • I wrote a first draft of the House Rules.
  • I set up all the digital tools we’d need.
  • I came up with a list of things to talk about (see the appendix to this post).

And then, feeling somewhat unprepared but generally hopeful, we began. Could I have done more? Sure. But don’t let the perfect be the enemy of the good.

Preparing for a session

There are two sorts of prep (I think):

  • Reviewing material I think the players will encounter.
  • Changing the dungeon based on the players’ actions.

Depending on what’s going on in the campaign, sometimes I need to do both, sometimes just one.

The first is just reading. If I think there’s a good chance of the players encountering something wildly different that would result in a lot of reading at the table—meeting a faction we’ve not seen before (or not seen in a while), visiting a new floor, engaging with some of the more complicated rooms, etc—I’ll review that material beforehand.

I kind of play this by ear. In practice my players don’t actually encounter brand new stuff that pre-reading benefits very frequently, as they tend to inefficiently bounce between a few different objectives for several sessions (because they’re not goal-oriented). But on the other hand, Arden Vul is massive, so even reading material which the players aren’t likely to see for a while is helpful, and makes reviewing it in the future (when it is likely to be relevant) quicker. So I’ve now read, or at least skimmed, all of the main dungeon levels and some of the sublevels.

The second is a bit more involved. Things the players do have knock-on effects: for example, I decided that them killing Gerrilad would lead to the baboons rising up against Isocritis, fighting to a stalemate where the baboons fear Isocritis and would attack him if they had the chance, but where they don’t encroach upon his territory around the library area.

So far I don’t have any specific tools for this beyond just staring at my notes and thinking. I try to get the dungeon back to a stable state fairly quickly. I’ve not felt the need to pull in any faction mechanics or similar yet. But that’s only because my players haven’t really got into the faction game yet; when they do, no doubt I’ll want factions to start moving and shaking things behind the scenes, and for the players to see the effects of that. I’m not sure what rules I will use, but I can figure that out later.

All that said, I know you all like procedures, so as far as I have a concrete “prep procedure,” here it is:

  1. Review previous session notes.
  2. Do any work left over from last time (e.g., converting spells or magic items from OSRIC and copying them into the player notes).
  3. Read any important material I think is likely to come up, or which just seems fun to read.
  4. Think hard about the current state of the dungeon and whether the last session should result in any changes, and then note those down.

My prep is fairly light. I expect it to get more complex over time, as the players inevitably get more involved with the major dungeon factions and the big secrets, but a pretty light touch gets you months of fun.

Running a session

I thought I’d start this section with a screenshot of my set-up:

My set-up for Arden Vul (with details obscured).

That’s right, three monitors. Two monitors are clearly better than one, and you know what’s even better than two? Anyway, here’s what I have open:

  • Firefox window with Miro, character sheets, player notes, etc (monitor 1)
  • Firefox window with a private dice roller and the donjon calendar (monitor 1)
  • Obsidian with my notes, minimised (monitor 1)
  • At least three copies of the main Arden Vul PDF (monitor 2)
  • Dungeon time tracker (monitor 2)
  • Arden Vul maps PDF and all the rules PDFs (monitor 3)
  • Discord (monitor 3)

Let’s go through some of those choices:

  • I just use Google’s dice roller for my private rolls. Yeah, it’s basic, but it does the job, and I only use it for the occasional thing, e.g. for random encounters.

  • Obsidian is minimised because my notes tend to be pretty brief. I’ll refer to them at the start of the session, and occasionally throughout the session, but I don’t need them up all the time.

  • Two copies of Arden Vul is really the minimum. One open on the current room description, one to use to reference other things. I like to have three in case I need to look up multiple things at once.

  • I have all the maps and rules in the same PDF reader because I figure if I’m actively consulting rules I’m probably not also using the map, whereas if I’m consulting room descriptions I probably am also looking at the map at the same time.

Obviously it’d be even better if I could have more of that displayed at once. Do I need a fourth monitor? Perhaps a second, smaller, landscape one mounted above the current one? Is that too much?

You probably don’t have three monitors, in which case you’ll need to either remedy that, or figure out what’s most important for you to be able to see all the time, and what can be relegated to the background.

On my desk I have:

  • The OSE referee screen, in case I need to reference anything there.
  • The physical Arden Vul books, open to the random encounter table for the current floor.
  • A pad of paper and a pen, to jot down rough notes as we play.
  • A pot of delicious tea, to keep my throat nice and lubricated.

The actual running of the session is basically the same as any other game:

  • I ask a player to give a recap of the previous session (I might fill in important details they miss).
  • I summarise the current state: the date and time, where the party is, what the current situation is, anything of immediate importance.
  • Then we begin: the players say what they do, I describe what happens, time advances, repeat.

After the session I distil my notes into what’s actually important (monster HP tracked in a battle, probably not important; a location partially looted, or an important NPC interacted with, probably important) and type it up into Obsidian, along with a list of things I need to do before next time (like adding any non-OSE spells they’ve found to the notes doc, or figuring out how an NPC will react to the events of the session). See the appendix to this post for an example.

So, no real Arden Vul-specific advice here. I guess that’s good, you don’t need to do anything different to how you usually run your games.

Parting words…

Here’s some final advice that didn’t really fit elsewhere but which I think is important to share:

  • The point of a secret is to be found.

    This is my number #1 guiding principle for running Arden Vul. There is so, so, much cool stuff in this dungeon. Most of it is hidden, beneath layers of history the players need to untangle, or physically behind secret doors. But it may as well not exist at all if it never sees play.

    Practically speaking, I won’t make inferences for the players, but I will remind them to check their notes—or ask probing questions—if I think they’re forgetting something or missing some connection. I won’t give them any information they haven’t earned, but I remind them to follow up on threads they’ve left unfinished.

  • Reward clever problem solving.

    This is my number #2 guiding principle. Or maybe a joint #1, as it’s also essential. Mostly, this comes down to letting the players just succeed at something if they have a plan which I think will work, or at least improving their chances if a roll is still involved.

    If a player comes up with a way to sneak up to the evil wizard undetected and stab them in the neck, good job, they insta-kill the evil wizard. I don’t “lose” by having “my” NPC die ingloriously. Similarly, if they come up with a way to circumvent a trap and there’s no reason it wouldn’t work, great, I want to see more of that sort of thing!

    Nothing kills creative thinking faster than feeling like it doesn’t matter.

  • Don’t overprepare.

    In every discussion of Arden Vul, you see people saying how daunting it is, the tremendous amount of prep required. And you certainly can prepare a lot. But I hope my example shows that you don’t actually need to read every room description, or convert every statblock, highlighting keywords and hyperlinking references, before you can even start.

    More prep can help, but the amount of required prep isn’t monumental. If preparing is fun and brings you peace of mind, go for it! Otherwise just do the bare minimum to start playing, your players will understand if you occasionally need to take a minute to read a long description or look up a reference.

  • Embace OSR principles.

    The Principia Apocrypha is a wealth of pithy advice for how to run this style of game. I periodically return to it and I never feel like the reread is a waste of time. Arden Vul is a megadungeon campaign setting written firmly in the old-school style. Embrace that.

There’s probably something I’m forgetting, more I could say, but in the spirit of not overpreparing: stop reading blog posts about Arden Vul and start that game!


Archontean calendar

# Season Real-world Ancient Modern Sunrise Sunset
- Winter - 1st Intercalary 1st Intercalary 08:00 16:00
1 January Patebrius Molivios 08:00 16:00
2 February Haenubrius Deuterios 08:00 16:30
3 Spring March Toterius Toternios 07:30 17:00
4 April Hosimirius Lucrios 06:30 18:00
5 May Sekremius Ligarios 06:00 20:00
6 Summer June Jelenius Jelenios 05:00 21:00
7 July Isiembrius Masporios 04:30 21:30
8 August Hohrarius Gerakios 05:00 21:00
- - 2nd Intercalary 2nd Intercalary 05:00 21:00
9 Autumn September Besemius Besemios 06:00 20:30
10 October Setherius Basilembrios 06:30 19:30
11 November Vadrius Dikaios 07:30 18:00
12 Winter December Draconis Fidios 07:30 16:30
  • Durations: Months are 30 days, intercalary periods 6 days
  • Day names: Basilsday, Lunday, Totsday, Mitrasday, Tasday, Horasday, Demmasday.

JSON for the donjon Fantasy Calendar Generator:

   "events" : 0,
   "first_day" : 0,
   "lunar_cyc" : {},
   "lunar_shf" : {},
   "month_len" : {
      "1st Intercalary" : 6,
      "2nd Intercalary" : 6,
      "Basilembrios" : 30,
      "Besemios" : 30,
      "Deuterios" : 30,
      "Dikaios" : 30,
      "Fidios" : 30,
      "Gerakios" : 30,
      "Jelenios" : 30,
      "Ligarios" : 30,
      "Lucrios" : 30,
      "Masporios" : 30,
      "Molivios" : 30,
      "Toternios" : 30
   "months" : [
      "1st Intercalary",
      "2nd Intercalary",
   "moons" : [],
   "n_months" : 14,
   "n_moons" : 0,
   "notes" : {},
   "week_len" : 7,
   "weekdays" : [
   "year" : 2993,
   "year_len" : 372

Common overland travel times

Distance 120 90 60 30
Gosterwick / The Long Stair (base) 9M (road) 2H 3H 4H 8H
The Long Stair (base) / The Long Stair (top) 3000ft (slick) 10T 14T 21T 42T
Gosterwick / The Long Stair (top) ~ 3.5H 5.5H 7.5H 15H
The Long Stair (top) / The Sign of the Broken Head 1750ft 5T 7T 10T 20T
The Long Stair (base) / The Sign of the Broken Head ~ 15T 21T 31T 62T
Gosterwick / The Sign of the Broken Head ~ 4.5H 6.5H 9H 18H
The Sign of the Broken Head / The Pyramid of Thoth 850ft 3T 4T 5T 10T
The Sign of the Broken Head / AV-12 North Tower 1350ft 4T 5T 8T 15T
  • 1 foot = 12 inches
  • 1 yard = 3 feet
  • 1 mile = 1760 yards = 5280 feet


Here’s the overall Miro board. The red dotted lines are level connections:

A very zoomed-out look at our Miro board.

Here’s a closer look at the roughly one-fifth of the Halls of Thoth that the party have explored:

The Halls of Thoth.

The Miro export doesn’t show it, but there is a grid there. We’re mapping at 5ft scale, as even though the Arden Vul map is at 10ft scale there are plenty of things offset by half a square or which are half a square big.

Session 0

These were my notes going into session 0. Before this I’d already pitched the idea of a megadungeon using some sort of OSR system to the players, so they were on board with the basic idea.

  • This session:

    • Campaign overview
    • Rules
    • Character (+ retainer) creation
    • Maybe start playing
  • Check access to Owlbear & Google Drive

  • The Halls of Arden Vul

    • What is a megadungeon?
      • A campaign-sized dungeon
      • Layers of history to uncover
      • Several factions to interact with
      • Treasures to find, monsters to fight, evils to overcome
      • It’s not just a huge dead place with the occasional zombie or skeleton
      • You can go anywhere at any time
      • I’ll need to call short breaks to consult the books from time to time
    • Archetypal D&D: high fantasy dungeoncrawling, traps, secret doors, maps, death around every corner, no plot armour
    • Very open-ended
    • No overarching plot, just an overarching location
    • You will need to take notes
    • Archontean Empire
      • Basically the Roman Empire
      • Arden Vul was an important administrative, military, scholarly city, the northernmost limit of the Empire on this continent (Irthuin)
      • Sacked and abandoned 1,200 years ago due to a civil war which forced the empire to contract
      • Recently the empire has returned to this continent
      • Gosterwick, adventurer town, founded 25 years ago
  • Good for irregular players:

    • No story to keep track of
    • NPCs to take control of
    • Just hop in for a single session
  • Rules:

    • OSE:AF (modern restatement of B/X D&D with some AD&D)
    • Plus house rules
  • Character creation

    • Roll up two characters each, one will be your PC the other a retainer
  • Rumours:

    • The best entrance is the Pyramid of Thoth
    • There’s an inn
    • Everyone roll 1d100 (adventuring), 1d30 (historical) for rumours (x2)
  • Start:

    • Roll starting date
    • Approaching the fall, near the Tower of Madness

Session notes

These are my notes for session 23 (with some player names excised), which the party began in 2-35 (Gerrilad’s throne room) about a week after they killed him.

This room has a big pile of coins, the way I handled that in the session was for the players to just carry out “unsorted coins,” and I wrote a little Python program to work out what they actually took afterwards. Alternatively, the players could have sorted the coins, and so they could have chosen what to take, but that would have taken in-game time and they didn’t want to do that.

tag: [2023-05-the-halls-of-arden-vul/session-notes]
link_style: session
date: 2023-11-05
game-date: 2994-Luc-10 to 2994-Luc-11
players: [PLAYER1, PLAYER2, PLAYER3]

# Intro

- Try standalone Discord client to see if that fixes PLAYER3's Miro audio issues
- Session recap

# State

- 10 Lucrios, 09:40
- In 2-35
- Accompanied by Tresti

# Prep

- Isocritis willing to negotiate with the PCs, but will put on a show of force (meet them accompanied by zombie baboons, with a wand in hand)
- Feats of exploration:
    - Manipulate or cripple a faction to your benefit (killing Gerrelad and throwing the baboons into chaos)
    - Confirm a rumour (location of the Library of Thoth)

# Notes

- **10 Lucrios**
    - Move all the coins behind the secret door
    - Meet Sisko and back away
    - Find the library and read Isocritis's note
    - Deal with Isocritis
        - They keep out of his area, and he doesn't care what they do

- **11 Lucrios**
    - Return to Gosterwick
    - Copy spells into Tresti's spellbook
    - Check with Creon if anyone's sold any glass squares - not yet

# Next time

- 12 Lucrios
- In the Gosterwick house
- [ ] Decide what benefits the hospital gives
- [X] Add spells to notes
- [X] Work out loot and XP
    - `{'cp': 4637, 'sp': 3883, 'gp': 1484, 'pp': 496}`
        - No loot XP for Tresti this time
    - 5%: Manipulate or cripple a faction to your benefit (killing Gerrelad and throwing the baboons into chaos)
    - 2%: Confirm a rumour (location of the Library of Thoth)
    - 2%: Uncover a secret (tunnels)

import random

coins = {
    "cp": 7562,
    "sp": 6293,
    "gp": 2365,
    "pp": 827,

retrieved = (1 + 6 + 4 + 5 + 10 + 4 + 7 + 14) * 100 + 2400 + 3000

out = {k: 0 for k in coins.keys()}

for _ in range(retrieved):
    choices = list(coins.keys())
    weights = [coins[k] for k in choices]
    choice  = random.choices(choices, weights=weights)[0]
    out[choice]   += 1
    coins[choice] -= 1

print(f"DRAW:      {out}")
print(f"REMAINDER: {coins}")