Hidden in Shadows

 Apparently there is a shirt for sale with the logo "It started with Blackmoor - 1975".  The date indicates they are referring to Blackmoor supplement II for OD&D, which was published in late 1975, but that makes the caption a bit strange and I don't think there is a similar shirt for Greyhawk Supplement 1, also published in 1975.

However odd the shirt may be, it brings up a good occasion to point out things that fans of Blackmoor often take for granted to the point of not realizing that not everyone knows them.  So, at the risk of pointing out the obvious to some, here is a list, no doubt incomplete, of things that actually started with Blackmoor:

The Dungeon

The 1960 edition of the classic Funk & Wagnalls standard dictionary of the English language defined dungeon as "A dark underground prison." Prior to Dave Arneson sitting down with paper and pencil and sketching out 6 levels of chambers and passages descending below castle Blackmoor, a dungeon was thought of as little more than a dank hole in the ground.

The Castle

Of course, castles in a fantasy game are a given and it was only natural for Arneson to use his lovely model of castle Branzoll in his Northern Marches game, but by doing this, and placing his extensive dungeon under it, he created the Castle/dungeon trope ubiquitous in D&D. In the real world, castles do not have multi-level underground labyrinths. In D&D they all do thanks to Dave.

What Arneson envisioned was new, but not unfamiliar, drawing on the images of caverns, catacombs and secret passages in monster movies, and the labrynths of mythology to create an amazingly complex vertical and horizontal underworld peopled with monsters. 

The Home Base

Also above the dungeon, the town of Blackmoor - apparently based on the wooden model of Cuidad Rodrigo as discussed in other posts - was almost certainly not initially conceived of as a home base where players could recharge and resupply between adventures.  I suspect rather we see Arneson once again replicating his beloved classic horror films. For what is a dark castle without a nearby village - a place where the protagonists can be forewarned of the danger and from which can spring a mob of angry villagers to storm the castle?  Of course there is also the fact that when Arneson began the Northern Marches campaign it was conceived of as a development of their "Braunstien" games which were always set in a town or city.  Nevertheless, functionally the town served exactly as a "home base" in D&D terms and the players, and for that matter Arneson, naturally understood the advantages the town provided for them. 

The Tavern

"You meet at an Inn". Surely this is the most used trope in fantasy role playing games ever and of course it is a trope that starts with Blackmoor.  Inspired by a real Come Back Inn in the Melrose Park neighborhood of Chicago, Arneson used his ComeBack Inn in the town of Blackmoor as a place for his players to gather to plan activities and gain information, just as thousands of GM's have after him. 

The General Store

There is no particular reason why characters in an adventure RPG should have to go shopping, yet it is a fundamental expectation of D&D.  Early in the Northern Marches campaign, Arneson created the general store, price lists for weapons and equipment, and placed Dan Nicholson in charge as "The Merchant. This sort of "local functionary" character was typical of their previous Braunstein games and a role Nicholson would have been familiar with.  He quickly took advantage of his de-facto monopoly to set up an underground shakedown network to ensure all the profits stayed with him - but that is another story.  In D&D, merchants and store-clerks were relegated to the GM as NPC's yet the activity of going to the store to haggle with the merchant over goods and services remains a typical part of the game.

The Cleric

Blackmoor had no classes, excepting, of course, all the classes Blackmoor had. Say what now? There were no classes as we know them in Blackmoor at all.  All characters were statistically the same regardless of what they did and a person could be pretty much whatever they wanted.  Thus at various times Dave Megarry played a thief, Dan Nicholson a merchant, John Snider was an imperial Inspector, etc., etc.  These roles didn't have mechanical components associated with them the way D&D classes do now, but differences began to arise that made some roles stand apart.  In particular wizards and priests grew to be "different".  For wizards the main difference was in how they advanced in spell levels and possibly in how they gained experience points.  For priests, the differences were more distinctive.  Priests gained the ability to cast healing spells and even to resurrect the dead.  This last ability appears to be tied to the deliberate and ultimately fatal risking of Greg Svenson's character by the other players while Greg himself was away in the summer of 1972.  As this death of a beloved character was not really fair to Greg, Arneson invented the idea that "The Great Svenny" could be resurrected by the clergy.  Subsequently a lot of resurrections occurred in the Northern Marches. Later, as vampires plagued the land, Priests also gained some abilities against undead - presumably skill at turning them. These distinctions set priests apart as effectively a different class.

Non-human Player Characters

Some of the earliest Blackmoor adventures were hexcrawls wherein the characters played themselves as transportees to the magical Northern Marches.  However players began to also play local characters and some of those local were not human. John Soukup, for example played a Balrog, Phil Grant played an elf prince, Walter Oberstar played a dwarf, Mel Johnson played a hobbit and Fred Funk played an orc. While today it is simply taken for granted that fantasy RPG have all sorts of non-human player character options, in the early 1970's this was an entirely novel idea.

Gothic Horror and Dune Salad

D&D players today take it for granted that they might face a medusae and a vampire in the same adventure - that's all due to Arneson's kitchen sink approach to the game.  If you look at CHAINMAIL, the fantasy wargame booklet that provided many monsters for the Northern Marches campaign, you will find only the classic monsters of Greek and Norse mythology with Tolkien flavoring added.  Arneson once again drew on his love of monster movies to mix such disparate monster types as Greek medusae, Gothic vampires, Fremen-like desert raiders and alien blobs in the same game.  Not only did such a crazy mix work, it worked brilliantly and is the basis of every monster manual and every D&D campaign since. 

Experience points for Killing Monsters and Treasure

Lastly, let me mention something that didn't quite begin with Blackmoor but for which Arneson is often credited - gaining levels of experience.  Arneson may well have coined the term "levels" and "leveling up" for growing more competent and powerful by stages, but in truth, the concept of advancement was a core part of the Strategos N rules for units.  "Green" units of recruits who survive a certain number of battles will improve to veteran status and can even become Elite.  Similarly, in Duane Jenkins Brownstone game started a few months just prior to Arneson's Northern Marches campaign, a character could go from being a nobody to a somebody over the course of several games. Jenkins doesn't seem to have had a unified mechanic for advancing player, and some roles appeared static, but Arneson seems to have solved or at least simplified that problem by awarding experience points for killing monsters and finding magical treasure.  He also created a system for wizards to gain new spells. It thus became a goal for all characters to "level up" to become better at killing monsters and to gain a bigger role in the game.

Supplement II Blackmoor by TSR didn't really start much, but the caption of the shirt isn't wrong. It did all start with Blackmoor.

 Yet another gamer firestorm arose shortly after the passing of Janelle Jaquays when it was noted that Justin Alexander had changed a rather well known post he had made in 2010 regarding dungeon design attributes he gathered from studying the games made by Jaquays.  In late 2023, as Jaquays was breathing her last, Alexander changed the term from Jaquaying to Xandering reportedly at the request of his publisher for his book "So You Want to be a Dungeon Master." Alexander also stated that Jaquays had requested that he change the name, which is true, but the request was only to change the spelling from Jaquaying to Jaquaysing because Alexander had left off the s. Thus the kerfuffle.

Okay, this post isn't a polemic on the rights or wrongs of what Alexander did.  In fact it's an old post I dusted off and finished in light of the controversy.  Jaquays deserves all the credit in the world for innovative game design. I'm a fan. The Catacombs Sourcebook is a favorite reference of mine and The Hell Pits of Nightfang is dear to my heart.  I'm quite sure that Jaquays deserves to be recognized for pioneering creative dungeon design.

I am going to say though, that seemingly unbeknownst to everybody including Jaquays, Arneson did it first.

There's a trope in science fiction of the old master years ahead of his time.  We see it in Highlander for example in the movies iconic katana impossibly made by a legendary master sword smith, Masamune in 593 B.C., or in Star Trek TNG, with the Master of Tarquin Hill who designed ceramic objects that were three hundred years ahead of their time.  This trope doesn't often have real world equivalents, the most obvious real example being Leonardo Da Vinci.

While Da Vinci was certainly appreciated in his day, the revolutionary and prescient nature of his more creative ideas was unappreciated until more recent times. Was Arneson the Da Vinci of dungeon design?

Below I've copied all the principles Alexander cites as core to "Xandering" a dungeon and examine each one in light of Arneson's principle early dungeon's  - Blackmoor Castle Dungeon (1972), and the Temple of the Frog Dungeon (1975). For good measure I will also throw in a few mentions of Tonisborg (1973) because as creator Greg Svenson will readily tell you, he copied Arneson's methods in designing the dungeon.  Here is the list:

MULTIPLE ENTRANCES: 

Blackmoor dungeon has more entrances than any dungeon I know.  Here is a partial list from the top of my head:

The Elf Stump

The Graveyard

Basement of the Silver Dragon Inn

Basement of the Church of the Facts of Life

The Wizard's Pit

The Well in the castle courtyard near SE corner of outer wall

Main Stair in the Throne room

Western corridor that leads to the hillside west of the Castle

The Temple of Id

Dragon Isle

Etc. etc.

The temple of the Frog dungeon has more than half a dozen entrances to the first level and at least 3 that go directly to the second.  Tonisborg also has multiple entrances.

MULTIPLE LEVEL CONNECTIONS: 

I did quick and dirty count of the Stairs in Blackmoor dungeon and came up with 73.  There are also about a half dozen fireshafts, multilevel caverns and so on.  The same is true of Tonisborg to a lesser scale.  Temple of the Frog dungeon has around a dozen connections between the two levels.

DISCONTINUOUS LEVEL CONNECTIONS: (connections that skip levels)

Blackmoor dungeon may well be the most vertically complex dungeon in existence to this day.  The 73 or so interconnecting stairwells, dozens of shafts and pits, vary from connecting only one level to another, to connecting at least ten levels.  Stairs also skip levels, sometimes only one, and sometimes several.    Tonisborg dungeon mimics this on a smaller scale.  

SECRET & UNUSUAL PATHS: 

Secret and unusual paths? Yes, in abundance.  Have a look at the tunnels for instance, secret entrances through the graveyard, the well, the wizards Pit, and various hidden caverns. There is also the hidden elevator shafts in a couple of the pillars of the Main Gallery.

Here is one Unusual Path on the first level:

SUB-LEVELS: 

This is a little harder to characterize.  Blackmoor, and Tonisborg have isolated sections that could be sublevels or not, depending on how you characterize them vertically.

DIVIDED LEVELS: (a level that cannot be completely traversed without going through the levels above or below it)

There are level sections in both Blackmoor and Tonisborg that can only be entered by going down one stair and up another or by finding, in some cases, a very difficult secret passage or in other cases by digging through a cave in.  Here is a small section example from level 2 entered only be secret doors or a stair:

NESTED DUNGEONS: 

Similarly, there are what one might call nested lairs only accessible through a secret entrance, for example from level 3:

MINOR ELEVATION SHIFTS: 

There are a couple of sloping areas in both Blackmoor and Tonisborg.  Temple of the Frog dungeon has both chutes and a sloping corridor covered with slippery slime.

MIDPOINT ENTRY

Tonisborg Dungeon's main entrance puts you on level 2. The well entrance to Blackmoor dungeon ends at level 3.  If you go in through any of the Blackmoor town entrances it will put you on level 4.  If you go in through the Wizards Pit you will enter on level 4 or 5.  etc.  The temple of the Frog has exterior entrances that put you on the bottom level (2).  So yes, not simply a midpoint entry, but multiple entries to multiple levels.

NON-EUCLIDEAN GEOMETRY

No this one I have to concede, isn't found in Blackmoor.  The references is to upside down rooms and M. C. Escher like passages.

EXTRADIMENSIONAL SPACES

A final point not to be missed is that all these design elements were incorporated by Arneson in the very first dungeon ever made. I'm not sure sure I can stress the enormity of this fact.  Arneson didn't need the years of trial and error that resulted in the design principles of "Xandering" that everyone else did. He intuitively grasped what would make a fun and challenging, repeatable dungeon experience from the moment he first put pen to paper in 1972.  I really find it quite amazing.  Blackmoor dungeon is truly a wonder of the fantasy world, like finding a digital camera in a 1972 time capsule.

 I had the pleasure of running Greg Svensons Tonisborg dungeon using the ZED rules at two conventions this year, and the results were interesting.

Tonisborg is a place not a challenge, so it is up to the DM to decide what, if any, scenario might be in play involving the player characters.  I chose to create an object centered adventure.  In other words, I wanted the players to chase after a specific Mcguffin instead of simply being loot hungry dungeon robbers or some such. 

Tonisborg provides ample opportunity for crafting scenarios because there are so many factions and so many curious inhabitants that must have a story behind thejr presence.

Partly because Tonisborg can be so deadly, and partly because it seems that high level play in 3llb style D&D is so rarely experienced.  I decided to go with 8-12 level characters, and further spiced the fun by handing out character sheets of original players.  For example, someone was playing Lord Oberstar, king of the dwarves.

For this adventure I picked an unnamed Lord and his small retinue found on level seven, and christened him Lord Kervall.  "Kervall" is a name that shows up in one of the MMRPG adventures as a minor noble family of Blackmoor, and I like Easter eggs.

So Kervall and his fours sons (the unnamed fighters with the unnamed lord) are in the dungeon. I decide, because the Kervall family has fallen out of disfavor with the King and Lord Kervall thinks if he finds the legendary crowns his star will rise.  

They have been gone 6 months when Lord Kervall sends a messenger to lady Kervall with partial dungeon maps and instructions to send reinforcements.  Long story short, she hires the party to bring him home instead.   

The first game took place at the Schenectady Wargaming Associations annual "Council Con" at the excellent Proctors Theater venue in downtown Schenectady NY.  This convention dates back to the mid 1970's and is a well attended event advertised in Dragon Magazine.  Known for years as "The Council of Five Nations" it was suspended during covid and was only just starting again under the shortened name.

I had a full table of participants and it was an orderly and thoughtful group.  Following an audience with Lady Kervall, the group journeyed to Tonisborg, met with a Lord Sheriff of the Order of Draconae, spent some time negotiating and questioning him, bought their passes and followed their guide to the dungeon entrance.

Now here is where my cheat for the players kicked in. The messenger from Kerval had given them partials maps with the correct stairs marked to get them to the lord more or less directly.  This was to facilitate the fact that this was a 4 hour convention game and there was no way they could wander Tonisborg and randomly find him.  Further, the route, if followed precisely, would be almost monster free.

This first group made contact with the Order Draconae guards on the second level, questioned them some more, and then proceeded cautiously into the dungeon.  They managed to follow the maps down to level 7 without incident, went around an area of yellow mold (marked on the map), and used an x-ray vision spell to move through a secret door and avoid an oncoming orc patrol.

An ESP spell outside the marked door helped them identify that they had found Lord Kervall and negotiations followed when the Lord refused to leave the dungeon but insisted they had come to help him. The party agreed and followed Kervall on further exploration.  However they soon found themselves in a room with a Cockatrice, which turned Kervall to stone.  Someone shouted to douse the lights and a brief combat entirely in the dark saw several wounds inflicted from friendly fire but some lucky strikes also killed the monster.  The party then convinced Kervall's sons that they really should leave the dungeon carrying the statue with them.

The second game was run at this year's Arnecon convention and followed much the same pattern as the first, but did differ in several ways.

Firstly the players, spent a lot more time discussing terms first with the Kervall messanger and then with Lady Kervall than the first group did.  Then when they arrived at Tonisborg, spent less time talking to the Order Draconae.  However, despite having very high level characters, this group thought that Tonisborg was so scary they needed extra muscle and so hired, following some lucky rolls and intense negotiations, an entire crew of Skandaharian sailors.  This proved interesting as the party then formed a very long group as it moved through the dungeon and they Skandaharrians alternated between bravado and skittishness.

This group avoided the Order Draconae guards on the second level, managed to take the wrong stairs on the fourth level (or was it the third?) and just managed to skirt by a black pudding hiding in the darkness of one of the large rooms they moved through.  In retrospect, I should have had them pudding attack them, but I decided it was in a particular place in the room and they didn't go there.

Anyway they managed to find their way to the correct stair after more discussion, and got back on track.  They passed through the room with Yellow Mold and one character was damaged.  This was the only HP loss of the entire session!  They too found lord Kervall, but instead of agreeing to adventure with him they found a way to overpower him and convince the sons to leave with them.

All in all, nobody died and the objective was achieved in both games.

What I want to highlight from both these games was that the role-play was constant, cooperation was intense, and smart play minimized combat.  Indeed the second game really had no combat at all. Tonisborg can certainly be a deadly dungeon. Old school games can certainly involve a lot of combat, but there is as much opportunity for role play heavy adventuring in Tonisborg or any other traditional dungeon, or in any traditional games, as there is in any "Modern" systems and adventures.

I've got a busy gaming schedule coming up.  I'm playing in Virtual Greyhawk con and running 2 games (Lakofka's Devils Dung and Lost Dungeons of Tonisborg) at SWA's Council 42 and thinking of also going to PAGE in January, but the highlight is ARNECON in October.

If you can make it, it will be a great chance for you to meet some of the games earliest players - oh and me if you wanted.  Here is the website with the basics:

ARNECON

If you happen to be in the Schenectady NY area and want to play in one of my games, check out the Schnectady Wargamers Council 42 just a few weeks from now:

Council

 Related to my last post, and a fun topic in itself, it is something of an open secret that the recent and ongoing "Chentoufi" series of adventures co-authored by Luke Gygax take place in a setting not unlike that his father Gary created in the western Flanaess.  Like the Arabian flavored Baklunish Empire of Greyhawk, the Arabian flavored empire of Luke Gygax's World of Okkorim was decimated centuries previously by a great magical devastation.

In both settings, the heart of the ancient empire was basically fried by a magical cataclysim, leaving behind a wasteland with a few outposts of struggling civilization at the edges.  In Greyhawk, the barren lands are known as "The Dry Steps". In Okkorim, its called the "Blighted Lands".

While I don't for a minute think Luke Gygax is trying to be sneaky here and give us Greyhawk with the serial numbers filed off, I do think it is not unreasonable to suppose Mr. Gygax is designing the Okkorim setting in a way that will (and does) make it easy for those who may wish to transplant his adventures into the Greyhawk setting. 

So how might we do that? Chentoufi is the city around which the various adventures take place.  It rests on a north-south coastline with ocean to the west and the Blighted lands to the east.

Thus we need to find a portion of the Flanaess of the right size with a north-south coastline, just west of the Dry Steppes which is the Greyhawk equivalent of the Blighted Lands.   There is one place, and only one place, that fits - maybe you guessed it - The Gulf of Ghayar.  Any further west on the Greyhawk map and you will leave the Dry Steppes  behind, not to mention there is not really a suitable coastline.

Remarkably, the eastern coast of the Gulf of Ghayar is mostly undeveloped in Greyhawk lore.  The Chentoufi coast can be plopped right in without much fuss.  Below is my attempt at doing just that.  

(Note I did rotate the Chentoufi map about 25 degrees NE in order to make the curving coastline on the bottom of the older line drawn map from the original release fit better to the Gulf of Ghayar coast.  I don't think the slight shift affects the geography very much,  The newer color maps of the Chentoufi coast don't go quite as far south and thus lack the coastal curve that necessitated the compass shift and it would be possible to re-align to North and still make the new color map fit if that were important to your game.  YMMV)

Sometimes I find myself moving along and minding my business when suddenly appears a rabbit hole and down I go. Heh.  Some of you will remember I did a couple of posts discussing and mapping the idea that Izmer, the realm setting of the first D&D movie, belongs to western Oerik and Greyhawk - the last post on the topic was HERE. 

Now a month or two back, a creative commons product came our called Beyond the Flanaess:Gulf of Ghayar Gazetteer., hosted on Anna Meyer's website HERE. If you are not familiar, the Gazeteer attempts to flesh out and expand the westward edge of the Flanaess beyond the Plains of the Paynim  into what is variously known as the Sundered Empire Map or Dragon Annual Map.  It basically covers some of the NW Flanaess and some of the NE Sundered Empire region - and this is of course the area there I had put Izmer.

I have a lot of irons in the fire so it takes me a while to get around to looking closely at new products and it wasn't until Friday that I took the time to look closely at this.  What struck me are the maps.  Troy Alleman has once again knocked one out of the park.

  However, Troy did something unorthodox, something I agree with 100%.  In order to explain the warm currents in the Dramidj ocean, Troy added a channel called the Omarra Straight separating the Flanaess from the Sundered Empire.  These maps are so good, I found myself wishing there was a way to fit in Izmer - and then I found one.  By creating the Straights of Omarra, Troy actually created the perfect spot - a mountainous peninsular region on the east shore of the new Straight.  Surprisingly, all that was needed was to move a few mountains, plant a couple rivers and forests, and viola., the locations transferred pretty much as I had them on the previous map. The resemblance to my previous Izmer map is striking, but I think this works even better. Here you go:

Now back to my regularly scheduled programming...

The Sahuagin are perhaps one of the most intriguing entries in Blackmoor Supplement II.  The creature was created by Steve Marsh, but here I want to explore the idea I proposed years ago that the Sahuagin story is more complicated.

Sahuagin is by far the largest entry for a sentient creature in the 1975 booklet.  Many of the others are only a few sentences or a paragraph at most.  A very good average comparison is Marsh's other creature the Ixitxachitl 

"A race of Chaotic Clerical Philosophers, they resemble Manta Rays (i.e. having a flat blanket-like form) with one in ten being a vampire equivalent (affected by any holy or blessed item, not just a cross). They are found in groups of 50–150 creatures with 40–120 being 1st-level philosophers (or clerics) and the rest of 2nd to 11th level (roll 10-sided die and add one). For every 25 such creatures there is a 50% chance of a magic user of the 6th to 11th level (roll 6-sided die and add six). For every vampire they possess one level F treasure, and one class “A” sea treasure for every magic user over 8th level; magic items cannot be used if hands are required (generally that means that only items that can be worn upon the body can be used)."

By comparison the Sahuagin entry is huge.  It looks like a double entry, and I think that is just what it is.

What follows is purely speculative - Let me repeat for clarity PURELY SPECULATIVE - but I think the anomalies found in this entry are best explained as a mash-up created by Supplement II editor Tim Kask of two separate creatures; one created by Steve Marsh and the other created by Dave Arneson.

First take note that the creature has two titles.  The first is "Sahuagin"  (Saw-gwin or Sa ha gwin - see Marsh explain HERE )

The second title follows in parenthesis as "Devil Men of the Deep"

Now, when discussing the origin of the name and creature Marsh explains the name Sahaugin was lifted from that of a Spanish historian cited in the bibliography of a Mormon missionary pamphlet and some of the details of the creature were inspired by a Justice League cartoon and/or comics.  This last is hard to pin down, but it is quite possibly the creature from a an Aquaman adventure in Superboy Vol 1 202 - which has a "half-man and half-fish" villain called the Devil-fish with characteristics quite similar to the Sahuagin. see HERE)

 THE SAHUAGIN 

Speculative Marsh version:  

In the eons past there was a great flooding of the land (although history does not agree when this occurred and it may have happened twice) when the ice caps were melted during a great struggle of the gods to control the planet. When the water rose some of these gods took care that representative portions of all life were preserved and returned when the waters fell and the land became fruitful again. Others sought to change the nature of life so it could adapt to the new face of the world and at the same time preserve its intelligence. Much about the Sahuagin is probably myth but even if half of what is said about them is true then they are, indeed, a terrible threat.With a huge leech-like mouth, large reptilian eyes, and huge ear-like growths on the side of their heads they have an almost alien appearance. On the upper body are two arm-like extensions that act as forward fins and end in two pincer-like protrusions (opposed to each other) which are used to grasp tools and weapons. The main body is reptilian in nature, covered with thick hide, and has a rudimentary tail which is used much like an alligator’s tail for steering and propulsion. The two rear legs are located about 2/3 of the way down the body and are long and frog-like, ending in a six-toed webbed foot which provides great stability when standing on soft sea bottoms and great propulsion when swimming. They have an average underwater speed of 18” with maximum speeds of up to 30” about once every hour. Their tough reptilian hide is similar to leather armor while the body can sustain two hit dice in damage. The mouth can be used to attach itself to or to rend the flesh of the victim with its hundreds of razor sharp teeth. The tail can deliver a pile driver-like punch similar to that wielded by a giant (club damage times two). The powerful pincers will crush anything up to or under bony composition they grasp (as daggers). The back feet can tear apart any victim that is grabbed by the forearms or otherwise act like the claws of a powerful animal. This formidable array is aided by the sensitive ears that can pick up underwater noise as slight as a boat’s oars cutting through the water at ranges of ten miles. The compound eyes are sensitive to light but can see through the darkest depths for up to half a mile (80–90”). Their disadvantages are that their eyes generally keep them 100’ or more below the surface, although at night or during storms they will reach the surface. Their ears are easily damaged by loud noises at close range and they cannot pick out the sound of swimming creatures (of any kind). 10–60 will be found in a single group with a 30% chance they will be in a lair with Class “F” and “A” treasure. The lair will be completely water-filled since these creatures cannot breathe air or fresh water at all. 

Now you may think that seems like a fairly complete entry, and it certainly compares well with Marsh's Sea Elves or the Ixichitl entries I quoted above, but there is quite a lot of text left - Enough for a whole other monster.

So now we come to what I'm suggesting originates with Arneson.  Unlike Marsh, we really have no clue from Arneson regarding Sahuagin.  Supposing I'm correct, he may have written about a "creature from the Black Lagoon" type monster, or perhaps an expansion on the lizardman, or, an intriguing possibility I'm going to follow here - a variant of The Sea Devils.

Sea Devils are in fact an amphibious undersea creature of the Dr. Who series, from episodes released in 1972.  Marsh never connected his Sahuagin to Dr. Who, yet the similarities are worth consideration.  Let me quote a description of the creature from the Doctor Who RPG:

"...Sea Devils, are ...2.1 to 2.3 meters tall. They are more turtle-like than are the Silurians, and they do not have a third eye. The five Silurian bone ridges have been replaced by two smaller head crests and by a beak-like nose. In addition to these differences, Sea Devils have adapted to underwater life. Although they are amphibians, Sea Devils can tolerate the extremely high pressures found near the bottom of the sea, and they can easily adapt to rapid pressure changes. Their thick, reptilian skin provides protection against extreme cold.

...Sea Devils are ruthless and relentlessly militaristic, and they have developed a highly advanced machine culture. They enjoy working with metals and wear protective armor at all times. " Doctor Who RPG (FASA)  Fantasy Simulations Associates   1985

It's curious that these undersea creatures are also called "Devils".  It's also curious that the Dr. Who Sea Devils, like what I'm positing is Arneson's contribution to the Sahuagin, has a very hierarchical, cruel and militaristic society.  Here is the remainder of the Sahuagin entry - what I'm calling the Arsoninan bit - with the word Sea Devil replacing Sahuagin:

Sea-Devils:

A constant threat to man, beast and fish are the voracious Sea-Devils whose only friends seem to be the equally voracious and predatory Giant Sharks. Although of an intelligence equal to the elves in many respects, the Sea-Devils have taken and perverted virtually every aspect of civilization to support their sadistic cannibalistic culture.   

It is said that the sea elves and the mermen were created by the Great Gods of Neutrality and Law while the Gods of Chaos bent their will to create the Sea-Devils. In every aspect the Evil ones sought to make the Sea-Devils into the most evil of the evil and many agree that they succeeded in making a race that fit that bill. Many individual horrors both on the land and sea may be in themselves worse than the Sea-Devils but nowhere will there be found a comparable race that as a whole retains the worst possible qualities.

When found in a lair there is a 10% chance that it is actually an underwater community of  100–1,000 creatures. There is then a further 20% chance that this community consists of 1,000–10,000 individuals. The underwater capital city has nearly 100,000 of these creatures residing within its watery limits. These cities will have great fighters and magic users as well asunderwater horrors that live and fight for the Sea-Devils. The ratio of these is as follows: 

per ten Sea-Devils there is a 25% chance of a double value fighter (Hero type)

per sixty there is a 15% chance of a triple value fighter (Superhero)

per one hundred of these individuals there is a 10% chance of a quadruple value fighter.

per five hundred of these individuals there is a 20% chance of a quintuple (5) times normal value fighter (Leader).

per one thousand individuals there is a 50% chance of a six times normal value fighter.

per forty there is a 30% chance of a 2nd-level magic user.

per one hundred there is a 25% chance of a 4th-level magic user.

per two hundred there is a 10% chance of a 6th-level magic user.

per five hundred there is a 25% chance of an 8th-level magic user.

per one thousand there is a 40% chance of a 12th-level magic user.

per group or up to sixty there will be 2–20 accompanying sharks.*

per group of one hundred there will be an additional 10–60 sharks.

per group of five hundred there will be an additional 20–120 sharks.

per group of one thousand there will be 100–400 additional sharks.

*(all totals for sharks are cumulative)

These creatures of evil are usually armed with the trident and the net — the former having a deadly poison on its tip and the latter having hundreds of small hooks set into its fabric. The Sea-Devils have become very adept at the use of both these weapons and these weapons also suit their temperament and regular habits. As an example, the small hooks in the net hinder escape while inflicting great pain on the live victims, and when torn from the flesh have the usual accompanying sharks driven into a frenzy from which they may attack the helplessly snared victims.

The tridents provide the ability to pin and probe the victims while not inflicting any mortal wounds (when the tips are unpoisoned) and allowing the Sea-Devils to remain at a safe distance.

Victims are usually brought to the nearest habitation (although only the ones with over 1,000 in population would have confinement cells for air breathing types) where they are either promptly eaten or penned in with some other predator to provide entertainment. The most common entertainment is to set the sharks on the victim, giving him only a small knife to defend himself. 

There are dozens of variations on the particular theme. Once captured there is very little possibility of escape and the sadistic nature of the captors has often allowed prisoners to think that they escaped only to be set upon by the sharks and guards when freedom (seemingly) is close at hand.

The culture of these creatures allows that there is only one King and he has only nine Princes with lesser positions being held as the situation and population demands. These leaders are always subject to challenge by any other member of the race to their position of leadership. The leaders are usually quite strong and several are reported to be mutations with four arms (this occurs in 1% of the population as a whole) and the fact that the Sea-Devils never cease to grow throughout their lives (much like reptiles) so that the leaders are also usually the older members of the species as well. Unsuccessful challengers are always killed and any cripples that occur in these fights are also disposed of, with especially unpopular types being tortured to death.

The disposal of the victims takes place at an after-the-challenge party where they are eaten by the other members of the group or community. This is also done with sickly members and others thought to be unfit to be a part of the community. The females are expected to bear their share of the fighting and are, visually at least, no different than the other members of the species.

The young are hatched from eggs and at birth, except for a few days right after birth, no different in size, strength, or viciousness than any other tribal member. The birth rate is about 15% a year and the average death rate about 10% a year.

Thoughts:

Notice that the original entry has two creation stories.  The first, which I'm pegging as the Arneson version specifically mentions the "Great Gods of Neutrality and Law" and "Gods of Chaos", phrases echoing the "Great Gods" mentioned in the FFC (77:21).

The second creation story involving a flood account I'm attributing to Marsh.  It is more detailed than the first and semi-biblical with certain qualities reminiscent to my ear of Marsh's Mormon faith.  The detailed creature description also fits best with Marsh's other entries and the " Class “F” and “A” treasure" also certainly does.

Whereas things like "100–1,000 creatures. There is then a further 20% chance that this community consists of 1,000–10,000 individuals" and  "per ten Sahuagin there is a 25% chance of a double value fighter (Hero type)" and " a quintuple (5) times normal value fighter (Leader)" are very Arnesonian.

In point of fact, Marsh never ever used phrases like "double value" etc.  but that is a characteristic and exclusive early Arneson thing in D&D published products as we have talked about several times before.  When asked by me about the meaning of this section with its double and triple values, Marsh was unsure what the terms meant.  Granted many years have passed, but I think it quite safe to say Marsh did not write this part of the Sahuagin entry.

Other characteristically Arnesonian features in this part of the entry include the references to captives being eaten and the inclusion of birth rates.  Overall it reads a lot like other Arnesonian monsters over the years.

Are my musings here correct?  Is the Sahuagin a mash-up from two different authors? Probably we will never know - but at the very least looking at the entries this way gives us two monsters for the price of one!