Can Adventurer, Conqueror, King Rpg Second Edition Rpg be used with original Dungeons & Dragons rpg ?!

 Yes, absolutely. In fact, Adventurer Conqueror King System II (ACKS II) and Original Dungeons & Dragons (OD&D) share the exact same mechanical DNA.

Because ACKS II is built on the foundation of the classic Basic/Expert (B/X) tradition—which itself was a direct stream-lining and evolution of OD&D—the two systems are highly compatible. You can easily lift elements from one and drop them into the other with minimal friction.

Here is a breakdown of how they cross over, where you will find the most value, and the few areas where you'll need to do a little quick math.

1. Where They Lock Together Perfectly

Because both systems use the same foundational "Old School" math, several core components require zero conversion:

• The Six Ability Scores: Strength, Intelligence, Wisdom, Dexterity, Constitution, and Charisma operate on the same 3–18 scale.

• Core Combat Stats: Hit Dice (HD), Hit Points (hp), and the concept of Armor Class (AC) function identically. If an OD&D monster has 3 HD, it translates perfectly to an ACKS II 3 HD monster.

• The Scale of the World: Movement rates, ten-minute dungeon turns, and one-day wilderness turns are completely synchronized.

2. The Best Ways to Combine Them

Most GMs who marry these two systems do so to fill the specific gaps each system has.

Using ACKS II to Supercharge an OD&D Campaign

OD&D (especially the 1974 "Little Brown Books") is famously loose and relies heavily on referee rulings. ACKS II is essentially the ultimate simulationist toolkit for that exact style of game. You can use ACKS II to provide:

• The Endgame (Domains & Kingdoms): If your OD&D characters reach high levels, OD&D gives very loose guidelines for castle-building. ACKS II gives you a flawless, mathematically airtight economic engine for investments, land management, taxation, and garrison costs.

• Trade & Commerce: Use the ACKS II mercantile rules to determine market classes for OD&D settlements and run trade-route campaigns.

• The Proficiency System: If your players want more distinct customization than OD&D's minimalist classes allow, you can overlay the ACKS II proficiency system directly onto OD&D characters.

Injecting OD&D Flavor into ACKS II

If you prefer the robust engine of ACKS II but want that weird, open-ended, high-fantasy 1970s flavor:

• Adventures and Monsters: You can run classic OD&D modules (like In Search of the Unknown or Keep on the Borderlands) using ACKS II rules. The stat blocks can be read straight off the page.

• Magic & Spells: You can introduce OD&D’s specific, sometimes looser spell interpretations into an ACKS II campaign as "lost" or "ancient" magic.

3. The Minor Friction Points (How to Fix Them)

While they are highly compatible, you will run into a few mechanics that don't match up perfectly. Here is how to smooth them over:

Ascending vs. Descending Armor Class

• The Friction: OD&D uses Descending AC (where AC 9 is unarmored and AC 2 is plate armor). ACKS II uses Ascending AC (where AC 0 is unarmored and higher numbers are better).

• The Fix: To convert an OD&D Descending AC to ACKS II Ascending AC, simply subtract the OD&D AC from 9.

  Example: An OD&D monster with AC 4 becomes AC 5 in ACKS II ($9 - 4 = 5$).

Attack Matrices vs. Throws

• The Friction: OD&D uses a combat matrix chart to look up what a character needs to roll to hit. ACKS II uses an "Attack Throw" target number (e.g., an Attack Throw of 10+ on a d20).

• The Fix: Use the ACKS II class progressions for combat. If you are importing a unique OD&D monster, look at its Hit Dice, find the matching Hit Dice row on the ACKS II monster attack table, and use that target number.

Saving Throws

• The Friction: OD&D uses five classic saving throw categories (Death Ray/Poison, All Wands, Turn to Stone, Dragon Breath, Spells). ACKS II streamlines these into five slightly different categories (Blast, Death, Gaze, Petrification/Paralysis, Spell) based on class.

• The Fix: Just use the saving throw values of the closest equivalent ACKS II class or monster HD. Don't sweat the structural difference; they cover the exact same mechanical hazards.

The Bottom Line: You don't need a complex conversion guide. If you treat ACKS II as the "advanced mechanics manual" for the world simulation, economy, and mass combat, and use OD&D (or its modules) for your core dungeon-crawling and class flavor, they fit together like glove and hand.

Using Gods, Demigods, and Heroes By Kuntz & Ward for original Dungeons & Dragons with Barrows and Borderlands Rpg

 Integrating the monumental 1980 supplement Gods, Demigods, and Heroes (Supplement IV) with Barrows & Borderlands (a modern "Old School Essentials" style hack) creates a high-powered, mythic campaign atmosphere.
This post picks right up from Using Original Dungeons & Dragons rpg with The Barrows & Borderlands Rpg 

While Original D&D (OD&D) provides the raw stats for deities, Barrows & Borderlands provides the grit and procedural exploration. Here is how to blend these two worlds effectively.

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1. The Role of Deities in Play

In Supplement IV, gods weren't just background lore; they were NPCs with Hit Points (often 300+), Armor Classes (frequently -10), and literal presence.

• The Power Scale: In Barrows & Borderlands, where a 1st-level Thief is incredibly fragile, a deity appearing is a "world-ending" event. Use them as Patrons or Cataclysms rather than combat encounters.

• Alignment Matters: Supplement IV categorizes gods by pantheon (Greek, Norse, Egyptian, etc.). Use these to define the "Borderlands." Perhaps the Lawful Norse gods hold the walled cities, while the Chaotic Egyptian gods rule the desert wastes.

2. Converting Stats to B&B

Since Barrows & Borderlands uses an OSR-adjacent chassis, the conversion is straightforward but requires some "squishing" to maintain the B&B lethality.

Attribute	Supplement IV Standard	B&B Implementation
Armor Class	Often negative (e.g., -2 or -10)	Convert to Ascending AC. An AC of -2 becomes 22; -10 becomes 30.
Magic Resistance	Percentage based (e.g., 75%)	Use as a flat "Saving Throw" bonus or a "Magic Immunity" trait.
Hit Dice/Points	Fixed HP (300+)	Keep the high HP. In B&B, this makes them virtually unkillable by mundane means.
Move	High inches (e.g., 24")	Triple the standard human movement rate.

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3. Heroes and Demigods as PC Benchmarks

Supplement IV introduces legendary figures like Hercules or Beowulf. In a Barrows & Borderlands campaign, these serve as the "Level 20+" endgame.

• Divine Spark: If a player reaches the level cap in B&B, allow them to quest for a "Spark" to become a Demigod. Use the Supplement IV stats as their new "Base Form."

• The Artifacts: Supplement IV is famous for items like Mjolnir or The Iron Crown. In the Borderlands, these shouldn't be found in a random chest. They should be the "Megadungeon" rewards at the bottom of the deepest Barrows.

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4. The "Borderlands" Theology

To make these gods feel authentic to the Barrows & Borderlands aesthetic, tie them to the landscape:

The Barrows (The Dead Gods)

Use the Egyptian or Sumerian pantheons here. These gods are often depicted as being obsessed with the afterlife. The "Barrows" aren't just graves for kings; they are prisons for demigods who refused to die.

The Borderlands (The Active Gods)

Use the Norse or Greek pantheons. These are "Wilder" gods.

• Odin might appear as a hooded traveler at a campfire in the Borderlands.

• Pan might be the source of the chaotic "Fey" energy that makes the woods so dangerous for B&B adventurers.

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5. Mechanical Integration: Clerics & Paladins

In B&B, Clerics usually choose a generic "Light" or "Dark" path. Supplement IV allows you to specialize:

1. Grant Specific Boons: A Cleric of Thor might gain +1 to damage with hammers (as per his Supplement IV description) but lose the ability to use "Command" spells.

2. Omens: Use the "Divine Intervention" percentages from Supplement IV. If a player performs a truly heroic feat, roll their Alignment % to see if a god notices.

A Note on Power Creep: Supplement IV is notoriously "overpowered" for standard OD&D. If you give a B&B player a "Hero" stat-line (18/00 Strength, etc.), they will trivialize standard monsters. Reserve these stats for temporary "Avatar" states or the literal end of a 5-year campaign.

 

Using Original Dungeons & Dragons rpg with The Barrows & Borderlands Rpg

 Barrows & Borderlands (B&B) is a "Weird Science Fantasy" tabletop RPG designed specifically to bridge the gap between the Original 1974 Dungeons & Dragons (OD&D) and 1st Edition Advanced Dungeons & Dragons (AD&D).

While it is heavily inspired by the "Little Brown Books" of the 70s, it isn't a mere clone; it's a "cracked-reactor" overhaul that blends high fantasy with post-apocalyptic sci-fi

Barrows & Borderlands (B&B) is a "Weird Science Fantasy" tabletop RPG designed specifically to bridge the gap between the Original 1974 Dungeons & Dragons (OD&D) and 1st Edition Advanced Dungeons & Dragons (AD&D).

While it is heavily inspired by the "Little Brown Books" of the 70s, it isn't a mere clone; it's a "cracked-reactor" overhaul that blends high fantasy with post-apocalyptic sci-fi.

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How They Connect: The Rules Bridge

Barrows & Borderlands uses the skeleton of original D&D but "bolts on" several mechanics to create a more robust, albeit "gonzo," experience.

Feature	Original D&D (0E) Influence	B&B Integration/Evolution
Core Classes	Fighting-Man, Cleric, Magic-User.	Adds the Thief, Gamma (mutant), and Psychic.
Combat	Based on Chainmail or the "Alternative Combat System."	Uses a hybrid 0E/1E system with added black-powder rules.
Magic	Vancian (memorize and forget).	Roll-to-cast sorcery that can "blow up in your face."
Stats	Minimal impact on rolls (mostly for XP bonuses).	Uses "Roll-Under" ability checks (d20 or 3d6) for tasks.
Psionics	Introduced in Eldritch Wizardry.	A dedicated system for psychic duels and wild powers.

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The Setting: "Solomon Kane vs. Rayguns"

The primary difference is the Atmosphere. While OD&D defaults to a Tolkien-esque or Jack Vance-style medieval world, B&B moves the timeline into a dark, radioactive wasteland.

• The Aesthetic: Medieval keeps and 17th-century pike lines exist alongside rusting star-metal and dead nuclear reactors.

• Radiation & Mutation: Borrowing from Metamorphosis Alpha, B&B introduces radiation sickness and complex mutation tables. You might play a Greenskull (an irradiated skeleton) or a mutant scavenger.

• Compatibility: B&B is intentionally designed to be OSR-compatible. You can take a classic OD&D module like Keep on the Borderlands and run it in B&B by simply swapping out standard goblins for irradiated mutants or "Data-Wraiths."

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Physical Design & Nostalgia

The game pays direct homage to the physical format of the 1974 original:

• The Box Set: It was released in a 4-volume set of light-tan booklets, mimicking the "Little Brown Books" of the 70s.

• The Art: It avoids modern high-gloss aesthetics and AI-generated images, opting for black-and-white pulp-style art that feels like it was drawn in a Midwest basement in 1975.

Note: If you are coming from modern D&D (5E), B&B will feel much more lethal and "swingy." It prioritizes player ingenuity and survival over balanced superhero-style combat.

OSR Commentary - OD&D volume 3: The Underworld & Wilderness Adventures (Jan 1974) By Gygax & Arneson

 

  So I was looking through the OSR Grimoire blog's entry on OD&D volume 3: The Underworld & Wilderness Adventures (Jan 1974). Original Dungeons & Dragons hits me square within the guts of my love for this hobby. And OD&D volume 3: The Underworld & Wilderness Adventures (Jan 1974) By Gygax & Arneson hits the wilderness & dungeon crawling bug right between the eyes. 
Back in 1974 I'd have been four years old but three years later I'm imagining my PC crawling through some slime covered moster infested  dungeon. Volume three covers;"The third volume of the original D&D rules is divided into three main sections.  The Underworld (covering dungeons), the Wilderness (including rules for establishing a domain), and rules for mass combat (land, aerial, and naval)."
This volume was especially important because it's literal DNA was in later editions; "Much of "The Underworld" section was incorporated into the Basic Rulebook edited by J. Eric Holmes (1977), and again in revisions edited by Tom Moldvay (1981), and Frank Mentzer (1983), creating an association between "Basic" D&D and the dungeon adventure."

In order to know where your going in this hobby, you have to know where we've been as players.  This is something I've observed about rpg's & wargaming as a matter of course. OD&D volume 3: The Underworld & Wilderness Adventures (Jan 1974) By Gygax & Arneson has the roots of expansion for the  DM to take thier original Dungeons & Dragons game to the next phase of campaign expansion. This of course is the Wilderness section;"

"The Wilderness" section involves overland exploration, castles/jousting, wandering monster tables, construction of castles/strongholds, specialists, men-at-arms, player/character support and upkeep, and baronies/domain management." OD&D volume 3: The Underworld & Wilderness Adventures gets into the heart of the wargaming/campaign aspects of OD&D; "
The final section of The Underworld & Wilderness Adventures provides rules for mass combat (Chainmail), aerial combat ("Battle in the Skies" or BITS, based on Mike Carr's "Fight in the Skies"), and naval combat (including special suggestions for monsters in naval adventures" Sure these rules were revisited and revised in "Swords & Spells" (1976). But the basics were there already and this  gets into my point there is a clear and defined linage of original Dungeons & Dragons running through Dungeons & Dragons right down into Mentzer Dungeons & Dragons.  This also includes the arerial combat rules;"Rules for aerial combat were derived from Arneson's "Battle in the Skies", demonstrated at Gary Con XI, this past March. " And having reread these rules they are nuanced. 
Basically,I'm still learning about and from the games that I love. And this is at least to me part of it's own reward. 

OSR Commentary - The Original Dungeons & Dragons Threat of The Warriors of Pan Tang

 “. Now he asked: “And who is this mighty sorcerer, Master Pilarmo?” “His name is Theleb K’aarna,” Pilarmo answered nervously. Elric’s scarlet eyes narrowed. “The sorcerer of Pan Tang?” “Aye—he comes from that island.” Elric put his cup down upon the table and rose, fingering his blade of black iron, the runesword Stormbringer. He said with conviction: “I will help you, gentlemen.” He had made up his mind not to rob them, after all. A new and more important plan was forming in his brain. Theleb K’aarna, he thought. So you have made Bakshaan your bolt-hole, eh?”
― Michael Moorcock, Elric: The Stealer of Souls

I've covered my interactions with the Stormbringer rpg's version of the Pan Tangians on this blog back in 2020  here. In the 80's I had a Games Workshop Pan Tangian Chaos army including tigers and more. My love of the Pan Tangians stretches back too original Dungeons & Dragons Kuntz & Ward's Gods, Demigods, and Heroes's Michael Moorcock Elric Mythos. The Pan Tangian warriors of OD&D are deadly; "PAN TANG WARRIORS Move etc. as men An army of fighters all able to fight with the ability of a 10th level fighter. These humans never check moral and ride a 6 legged reptile which stands 15 feet tall and moves 20" per turn." What made them deadly was two fold, one is that these warriors could show up anywhere and they were deadly tenth level fighters! 

During the Eighties in my uncle's original Dungeons & Dragons game campaigns we crossed swords with the Pan Tangians numerous times. And died at least three or more times. 

And one of the things that made the Pan Tangian armies so deadly was thier trained and Chaos tainted tigers. These tigers were always accompanying the warriors of Pan Tang; " FIGHTING TIGERS OF TANG Armor Class — 4 Fighter Ability: As Tigers Move: 19" Psionic Ability: Class 6 Hit Points These are 10 feet tall tigers able to bite for 4 (8-sided) dice of damage and claw for 3 (8-sided). They always appear beside the Pan Tang warriors, one to a mount."  My uncle's own 15 MM Pan Tangian army was our adventurer's bane through out or campaign and beyond. It wasn't until the 90's that we learnt that it was actually a Pan Tangian agent with his own private army of mercenaries who dogged our heels. In fact, in part three of   'The Madcap Laughs' were introduced to a hunch backed Pan Tangian sorcerer Ylastraraa Taar who has an agenda all of his own for the PC's. This NPC managed to survive the events of 'The Madcap Laughs' & then plague the PC's for more then a year of play.

That twisted little S.O.B. followed us from the Young Kingdoms to Greyhawk then across the Million Spheres! That slight could be traced back to our original Dungeons & Dragons Greyhawk folio campaign when we were doing guard duty for a trade caravan to Pan Tang.. That's right one NPC dogged our party for a whole two  year span from '89 through '91.  

OSR Commentary - Original Dungeons & Dragons, The Great Wheel Cosmology, & The Dragon Issue #8

 When it comes to Original Dungeons & Dragons & the planes of existence there's one magazine that's critical and that's 'The Dragon' magazine issue #8. This blog entry is actually going to pick from our commentary on the Manual of the Planes here on the blog. 

And this is because of the Gary Gygax article "The Concepts of Spacial, Temporal and Physical Relationships in D&D" This is the first mention and definition of the familar 'Great Wheel'. And according to the Forgotten Realm Wiki entry on 'The Dragon issue #8 we get the gammit of planes;"

Locations

Planes: Astral Plane • Elemental Planes • Ethereal Plane • Inner Planes • Negative Energy Planes • Positive Energy Planes • Prime Material Plane • Outer Planes

Elemental Planes: Elemental Plane of Air • Elemental Plane of Earth • Elemental Plane of Fire • Elemental Plane of Water

Outer Planes: Abyss • Acheron • Arcadia • Elysium • Gehenna • Gladsheim • Hades • Happy Hunting Grounds • Limbo • Nine Hells • Nirvana • Olympus • Pandemonium • Seven Heavens • Tarterus • Twin Paradises" 

Mr.Gygax lays out the fundamentals right off the bat in The Concepts of Spacial, Temporal and Physical Relationships in D&D";
"For game purposes the DM is to assume the existence of an infinite number of co-existing planes. The normal plane for human-type life forms is the Prime Material Plane. A number of planes actually touch this one and are reached with relative ease. These planes are the Negative and Positive Material Planes, the Elemental Planes (air, earth, fire, water), the Etherial Plane (which co-exists in exactly the same space as the Prime Material Plane), and the Astral Plane (which warps the dimension we know as length [distance]). Typical higher planes are the Seven Heavens, the Twin Paradises, and Elysium. The plane of ultimate Law is Nirvana, while the plane of ultimate Chaos (entropy) is Limbo. Typical lower planes are the Nine Hells, Hades’ three glooms, and the 666 layers of the Abyss. Assume further that creatures which can be harmed only by weapons of a special metal (silver, cold iron, etc.) gain this relative invulnerability from having a portion of their existence in either the positive or negative material plane at the same time they exist partially in the prime. Therefore, those creatures which can be struck only with + 1 or greater magical weapons exist wholly and simultaneously in two planes (one of which is, of course, the Prime Material). So creatures which require attack of a + 2 or better magic weapon then exist in three planes simultaneously, and so on. This brings us to the consideration of the existence of magical weapons in other planes and in multiple planes simultaneously." 

And this goes back into original Dungeons & Dragons wargaming roots according to the same article;"As a side benefit of the use of this system, operation on the astral or ethereal by characters no longer poses such a headache to DMs. As magic weapons exist in those planes which touch upon the Prime Material Plane, any person armed with a magic weapon will be able to attack into the Astral or Ethereal Plane if they become aware that their opponent is operating in one of these planes. Finally, what of magic swords of special nature or special purpose which are far removed from the Prime Material Plane? I suggest that these weapons can be removed no further than the number of planes from the Prime Material which equals their best bonus stated as a “to hit”, i.e. a + 2 can be removed by two planes and still retain its magical properties. Certain swords will have special treatment — the sword of sharpness and the vorpal blade most notably. On the other hand, a sword of life draining ability gains no such consideration, for it operates primarily on the Negative Material Plane. In any event, swords removed beyond the plane limit given will lose all of their magic, becoming nothing more than normal weapons. This same “law” can apply equally to those weapons, swords or otherwise, which have a simple “to hit” bonus." " And below is the 'Great Wheel' and yes it's from Kuntz and Ward's Gods & Demigods for AD&D first edition but it's very easy to read.  You can read about the Great Wheel cosmology here for even more clearity. 

What the Gary Gygax article "The Concepts of Spacial, Temporal and Physical Relationships in D&D" is doing is simultaniously setting up planar travel for original Dungeons & Dragons. And this article is also laying the groundwork for planar travel to be a high level occurance in Advanced Dungeons & Dragons coming up. 
Everything in the Gary Gygax article "The Concepts of Spacial, Temporal and Physical Relationships in D&D" is layed out and colour coded. Is it easy to use? Yes and no, if the DM wants to do some of the work of getting the planes into his or her original Dungeons & Dragons game. The ground work is right there.