Running classic 1st Edition Advanced Dungeons & Dragons modules—specifically the iconic G1-3 Giant Series (Steading of the Hill Giant Chieftain, Glacial Rift of the Frost Giant Jarl, and Hall of the Fire Giant King by Gary Gygax)—using Adventurer Conqueror King System II (ACKS II)

 Running classic 1st Edition Advanced Dungeons & Dragons modules—specifically the iconic G1-3 Giant Series (Steading of the Hill Giant Chieftain, Glacial Rift of the Frost Giant Jarl, and Hall of the Fire Giant King by Gary Gygax)—using Adventurer Conqueror King System II (ACKS II) is an exceptional match. Both systems share deep B/X D&D roots, but ACKS II brings tighter domain mechanics, refined tactical combat, and precise mass battle options. This blog post picks right up from OSR Module Campaign Commentary - D1-2: Descent into the Depths of the Earth using Adventurer Conqueror King System II (ACKS II) Combined With ACKS II rpg

  

Here is a comprehensive guide to adapting, running, and managing the G1-3 series in ACKS II.

1. Monster & Stat Conversions

Because ACKS II is built on the OSR/B/X foundation, converting 1E stats to ACKS II can largely be done on the fly, but a few key adjustments are needed to account for ACKS II's specific balance.

Giants & Big Monsters

• Hit Dice & Attack Bonus: In AD&D 1E, Hill Giants have 8+1–2 HD, Frost Giants have 10+1–4 HD, and Fire Giants have 11+1–4 HD. In ACKS II, use their standard ACKS Monster Manual hit dice:

  • Hill Giant: HD 8*, AC 4 (15), Damage 2d8 or 3d6 (boulder)

  • Frost Giant: HD 10*, AC 5 (16), Damage 2d10 or 3d8 (boulder)

  • Fire Giant: HD 11, AC 6 (17), Damage 3d6 or 3d10 (boulder)

• Cleave Mechanics: Remember that ACKS II combat uses Cleave. High-level giants facing level 1–3 retainers or hirelings will slice through multiple targets per turn. Warn your players: sending weak hirelings into melee against giants will result in a bloody cascade.

• Saving Throws & Morale: Use ACKS II creature saves corresponding to their HD. Set Giant Morale to +1 or +2 initially; however, once leadership (Chieftain, Jarl, King) falls, drop Morale checks across the complex to -1 or -2.

Drow & Dark Elves (Module G3)

• Translate 1E Drow directly to ACKS II Elven Spellswords or Elven Nightblades for NPC statlines.

• Replace 1E magic resistance (% MR) with the ACKS II Saving Throw bonuses against Magic or apply the Spell Resistance monster quality.

2. Converting AD&D Treasure to ACKS II Economy

AD&D G1-3 is famously packed with astronomical amounts of gold, gems, and magic items designed for high-level 1E experience progression. ACKS II ties Gold to XP (1 GP = 1 XP) and directly anchors wealth to domain-building and army upkeep.

1. Reduce Raw Coinage by ~30–50%: Left as-is, G1-3 will instantly catapult ACKS II characters straight into high-tier domain ownership overnight. Scale down hoard values slightly or convert excessive gold/gems into trade goods, raw materials, or domain assets.

2. Value Magic Items via ACKS II Rules: AD&D magic items often lack strict gold valuations. Use the ACKS II Judge’s Journal item creation and market cost values to determine GP equivalencies for XP when magic items are recovered or sold.

3. Adapting the Campaign Structure to ACKS II Playstyles

G1-3 is traditionally run as an extended tactical dungeon crawl, but ACKS II opens up three distinct ways to handle the campaign:

                      ┌─────────────────────────┐
                      │    The Giant Incursion  │
                      └────────────┬────────────┘
                                   │
         ┌─────────────────────────┼─────────────────────────┐
         ▼                         ▼                         ▼
┌───────────────────┐    ┌───────────────────┐    ┌───────────────────┐
│ Tactical Commando │    │ Domain & Siege    │    │ Mercenary Company │
│ (Standard Crawl)  │    │ Warfare (War-Engine)│  │ Campaign (Company)│
└───────────────────┘    └───────────────────┘    └───────────────────┘

Option A: Tactical Commando (Standard Adventuring)

The party operates as a high-level strike team infiltrating enemy strongholds.

• Morale & Alarm Cycles: Giants aren't static dungeon monsters. If the party strikes the Steading and retreats to rest, the Hill Giants will fortify entrances, set ambushes, coordinate with nearby camps, or counter-attack the party's basecamp.

• Mortal & Injury Tables: Use ACKS II's Mortal Wounds and Tampering With Mortality tables. Taking a direct blow from a Fire Giant's greatsword rarely results in instant death—it results in broken ribs, severed limbs, or permanent scars, keeping the survival horror tone alive.

Option B: Domain & Siege Warfare (ACKS II War-Engine)

Rather than 6 adventurers raiding a fort, the local realm hires the PCs as Barons/Generals to lead a military campaign against the giant threat.

• Mass Combat: Convert the Steading (G1) or Glacial Rift (G2) from a dungeon map into a fortified stronghold defended by giant garrisons.

• Use the ACKS II War-Engine rules to resolve siege weapons, platoon-scale giant clashes, and vanguard assaults.

• The PCs lead elite units (heavy cavalry, battle-mages) to breach the gates before transitioning into man-to-man skirmishing inside the interior halls.

Option C: Mercenary Company

The PCs operate an ACKS II Mercenary Company contracted by the High March or Grand Duchy.

• The PCs manage logistics, supply lines, scout reports, and wage payouts for specialized vanguard troops (e.g., dwarven sappers, elven archers) while taking on the primary command goals inside G1–G3 themselves.

4. Key Rules Adjustments Summary

Feature	AD&D 1st Edition	ACKS II
Armor Class	Descending AC (THAC0 / Tables)	Ascending AC (Base 0 + Armor/DEX)
Giant Boulder Throwing	Direct rock attack tables	Ranged missile attacks using ACKS weapon ranges & cover
Surprise & Stealth	Percentile / D6 roll	ACKS II Proficiency system (e.g., Shadowing, Skulking)
Retainers / Hirelings	Basic loyalty scores	Detailed Morale & Loyalty checks modified by CHA & domain rank
Movement & Encumbrance	Inches (") / Segment actions	Stride-based tactical movement and stone-based encumbrance

5. Campaign Flow & Hooks

1. G1 (Hill Giants): Set in the borderlands of a human realm. The local ruler offers land grants, fiefs, or noble titles in ACKS II terms as the reward for neutralizing Chieftain Nosnra.

2. G2 (Frost Giants): High-altitude wilderness travel. Use ACKS II Wilderness Navigation & Encounters rules to make reaching the rift a brutal expedition testing supply lines and cold-weather gear.

3. G3 (Fire Giants): Deep subterranean domain. Incorporate ACKS II Sinkhole & Underworld rules as the party descends into the volcanic fortress of King Snurre and uncovers the Drow conspiracy.