OSR Adventure Fodder - d100 random encounter table designed for a high-octane 1930s pulp adventure, optimized for Amazing Adventures (using SIEGE Engine / d20 OSR math)

 Here is a d100 random encounter table designed for a high-octane 1930s pulp adventure, optimized for Amazing Adventures (using SIEGE Engine / d20 OSR math) while drawing on the tropes, villains, and modules of the Pulps. This post picks up from OSR Campaign Slab - Amazing Adventures Rpg - Weird War II Campaign

Pulp Adventure Wilderness & Remote Front-Line Encounters (d100)

• SIEGE Check Base: Primary = CL 12 | Secondary = CL 18.

• Fate Points: Major threats allow spending 1 Fate Point to double effect or avoid instant death.

d100	Encounter / Event	Mechanics & Features
01–05	Rogue Biplane Strafe	An unflagged Curtiss Jenny dives out of the clouds with machine guns blazing. Vehicle HD 4, AC 15, Pilot SIEGE Dexterity check to evade.
06–10	Cult of the Obsidian Eye	2d6 Cultist Zealots ambush from concealment, wielding poisoned kris daggers. HD 1, AC 12, Poison requires SIEGE Constitution check.
11–15	Thundering Stampede	A panicked herd of rhinos, dinosaurs, or wild cattle charges through camp. SIEGE Dexterity or Strength check to dodge/divert; failure = 3d6 bludgeoning.
16–20	Mercenary Patrol (Thule Syndicate / Red Star)	1d6+2 uniformed mercenaries led by a ruthless Squad Leader with a Thompson submachine gun. HD 2 (Leader HD 4), AC 14, Automatic Fire rules apply.
21–25	Quicksand / Tar Pit Hazard	The lead character steps into treacherous mud or ancient pitch. SIEGE Strength check to break free before sinking in 1d4 rounds.
26–30	Mad Scientist’s Automaton	A clanking, 8-foot brass automaton powered by a glowing vacuum tube heart. HD 6, AC 18 (Hardness 5), Vulnerable to electricity or targeting the heart tube.
31–35	Rival Archaeologist / Treasure Hunter	A charismatic rival (e.g., Femme Fatale or Dashing Rogue) offers a temporary truce—or steals a key map fragment while camp sleeps. SIEGE Wisdom (Insight) to catch.
36–40	Cryptid Attack (Yeti / Ape-Man)	A giant primeval ape hurls boulders from high cliffs before charging into melee. HD 5, AC 14, Hurls boulders (2d8 damage, Range 60 ft).
41–45	Ruin Trap: Pressure Plate & Pendulum	Collapsing ancient ruins trigger a swinging blade or dart volley. SIEGE Dexterity check to avoid; 2d10 damage.
46–50	Stranded Airship / Plane Wreck	A downed cargo plane suspended in the jungle canopy. Contains 1d4 supply crates (Ammo, Rations, Dynamite) guarded by starving predators.
51–55	Venomous Swarm (Locusts / Driver Ants)	A wall of biting insects sweeps through the area. Requires immediate movement or fire/smoke to disperse; 1d4 damage/round + blindness.
56–60	The Mysterious Hermit / Mystic	An old monk or exiled scholar who shares a cryptogram leading to a nearby tomb if treated with respect.
61–65	Ghost Ship / Derelict Truck Convoy	Abandoned vehicles with strange, frost-covered interior or burnt markings—hints at occult experiments nearby.
66–70	Occult Ritual in Progress	A High Priest and 1d4+1 acolytes channeling a dimensional rift. A summoned Lesser Fiend or Shadow Horror emerges in 1d4 turns if unbroken.
71–75	Poison Dart Trap Network	Hidden tripwires set by hostile native tribes guarding forbidden borders. SIEGE Intelligence or Wisdom check to spot; 1d6 damage + Sleep Venom.
76–80	Armored Half-Track Patrol	A heavily armored truck with a mounted machine gun or flamethrower patrolling dirt trails. Vehicle HD 6, AC 17, Mounted Gun 3d6 damage.
81–85	Volcanic Fissure / Earth Tremor	The ground splits open emitting toxic sulfur gas. SIEGE Constitution check or suffer 1d6 poison damage and choking.
86–90	Giant Reptile / Megalania	A 20-foot monitor lizard or surviving Carnotaurus hunting for meat. HD 7, AC 15, Bite & Grab attack (2d8+4).
91–95	Hypnotic Sound / Psychic Resonance	A strange frequency emanating from an ancient monolith. SIEGE Charisma check or become charmed/confused for 1d6 rounds.
96–99	The Nemesis Arrives	The campaign’s recurring Mastermind or Archnemesis appears with 2d4 elite henchmen, demanding an artifact or offering a sinister ultimatum.
100	Ancient Kaiju / Awoken Elder Entity	The earth shakes as a massive 50-foot guardian construct or elder beast rouses from slumber. HD 12+, Requires heavy explosives, artillery, or ancient levers to defeat.

Running Encounters in Amazing Adventures

• Initiative: Simple d6 roll per side (High roll goes first).

• Cinematic Action Checks: Allow players to use Fate Points or attempt creative SIEGE attribute checks (e.g., swinging on vines using Dexterity, shooting fuel tanks using Intelligence) to resolve combat through pulp spectacle rather than slow attrition.

A Deeper Look into Combining Dave Hargrave’s gonzo, over-the-top Arduin Grimoires with the rigorous, simulationist campaign structures of Alexander Macris’s Adventurer Conqueror King System II (ACKS II)

 

Combining Dave Hargrave’s gonzo, over-the-top Arduin Grimoires with the rigorous, simulationist campaign structures of Alexander Macris’s Adventurer Conqueror King System II (ACKS II) turns chaotic high-fantasy into a highly functional campaign world.

System Synergies & Design Mechanics

Integrating these two Old School Renaissance (OSR) titans requires blending ACKS II's macro-level mechanics with Arduin's micro-level combat lethality and techno-magical strangeness:

• Domain Mechanics vs. Technomagic: ACKS II provides strict rules for population investment, land clearing, trade routes, and stronghold revenue. Arduin injects technological oddities (e.g., power cells, glass-steel weapons, phantasmal engines). In an ACKS II framework, Arduin artifacts can be treated as Domain Special Resources that grant bonus revenue, reduce stronghold upkeep, or act as siege engines.

• Mortal Wounds & Arduin Criticals: ACKS II uses a structured Mortal Wounds table to determine character fate upon reaching 0 HP. You can seamlessly map Arduin’s iconic Critical Hit & Fumble Charts directly into ACKS II's combat flow: natural 20s force an immediate roll on the Arduin Critical Hit table, overriding standard weapon damage while keeping ACKS II's cleave and combat maneuver rules intact.

• Class & Race Integration: Standard ACKS II relies on strict race-as-class templates (e.g., Elven Spellsword). Arduin’s unique races—like the insectoid Phraint, reptilian Saurig, or heavy Amazonian Skynauts—can easily be built using ACKS II's Custom Class Creation Engine by assigning hit die steps, fighting value, and special racial proficiencies.

Detailed Monster Conversion: The Phraint Soldier

To demonstrate direct system conversion, here is a complete stat block for Arduin’s iconic mantis-like warrior built directly into ACKS II mechanics.

• Armor Class: 5 (Exoskeleton + Agility, equivalent to ACKS II Scale)

• Hit Dice: $3d8+3$ ($16 \text{ hp}$)

• Attacks: 2 × Leaping Claws ($1d6$) or 1 × Arduin Glass-Steel Longsword ($1d8+2$)

• Save: Fighter 3

• Morale: +2

• Alignment: Neutral

• Movement: 120' (40') / Leaping 180' (60')

• ACKS II Fighting Tier: Tier 2 (Cleaves up to 3 times per round against $1\text{-HD}$ foes)

• Special Traits (Arduin/ACKS II Combined):

  • Spring Jump: Can leap up to 60 feet into combat, ignoring frontline positioning to directly engage backline spellcasters. Grants +2 to Hit on the turn it leaps.

  • Chitinous Resilience: Immune to non-magical sleep, hold, and mind-affecting effects.

  • Glass-Steel Equipment: Weapons ignore 1 point of enemy Armor Class and never break on critical fumble rolls.

The Phraint is Arduin’s iconic insectoid warrior—a tall, sleek, mantis-like humanoid built for blinding speed, vertical leaps, and relentless precision. Using the ACKS II Custom Class Creation Engine, this class combines martial prowess, natural armor, high mobility, and insectoid traits.

Class Build Mechanics (ACKS II Engine)

• Base Race: Phraint (Custom Demi-Human Base)

• XP to Level 2: $2,200 \text{ XP}$

• Hit Dice: $1d8$ per level (up to Level 9, then $+2 \text{ hp}$ per level)

• Maximum Level: 14

Category Point Allocation

• Demihuman (Phraint): 1 Category Point

  • Traits: Chitinous Exoskeleton ($AC\ 4$ base, equivalent to scale armor), Spring Leap, Insectoid Mind (immune to Sleep and Charm), Compound Vision ($120\text{'}$ Darkvision, $-2$ chance to be surprised).

• Fighting: 2 Category Points

  • Combat Progression: Fighter/Martial attack throws ($+1$ to hit every 2 levels).

  • Weapon Skills: Broad access to melee and missile weapons.

  • Cleaves: $1$ Cleave per level up to character level (max $14$).

• Magic: 0 Category Points (Non-caster)

• Thievery: 1 Category Point

  • Skills: Acrobatics, Stealth, and Climbing progression.

Phraint Level Advancement Table

Level	Experience	Hit Dice	Attack Throw	Save	Cleaves/Rnd	Special Abilities
1	$0$	$1d8+1$	$10+$	$14+$	$1$	Exoskeleton ($AC\ 4$), Spring Leap, Compound Vision, Insectoid Mind
2	$2,200$	$2d8+2$	$9+$	$13+$	$2$	Uncanny Dodge
3	$4,400$	$3d8+3$	$8+$	$12+$	$3$	Martial Proficiency
4	$8,800$	$4d8+4$	$7+$	$11+$	$4$	Precise Strike ($+1$ Damage)
5	$17,600$	$5d8+5$	$6+$	$10+$	$5$	Bound Leap (Double distance)
6	$35,200$	$6d8+6$	$5+$	$9+$	$6$	Chitin Hardening ($AC\ 5$)
7	$70,400$	$7d8+7$	$4+$	$8+$	$7$	Pounce Attack
8	$140,800$	$8d8+8$	$3+$	$7+$	$8$	Martial Proficiency
9	$280,000$	$9d8+9$	$2+$	$6+$	$9$	Hive Commander (Establish Hive-Fortress)
10	$400,000$	$9d8+11$	$1+$	$5+$	$10$	Precise Strike ($+2$ Damage)
11	$520,000$	$9d8+13$	$1+$	$4+$	$11$	Chitin Hardening ($AC\ 6$)
12	$640,000$	$9d8+15$	$1+$	$3+$	$12$	Martial Proficiency
13	$760,000$	$9d8+17$	$1+$	$2+$	$13$	Apex Predator (Immune to Fear)
14	$880,000$	$9d8+19$	$1+$	$2+$	$14$	Master of the Hive

Class Features & Racial Traits

• Chitinous Exoskeleton: A Phraint's natural armor grants an base $AC\ 4$ at Level 1 (does not stack with worn body armor, but shield modifiers apply). Increases to $AC\ 5$ at Level 6, and $AC\ 6$ at Level 11.

• Spring Leap: Once per turn, a Phraint can leap up to $60\text{'}$ forward or $30\text{'}$ vertically as part of a movement action. This bypasses frontline terrain and enemies to reach backline targets.

• Compound Vision: Wide-angle multi-faceted eyes grant $120\text{'}$ Darkvision and a $-2$ bonus to surprise rolls (surprised only on a $1$ on $1d6$).

• Insectoid Mind: Alien biology renders Phraints completely immune to Sleep, Charm, and non-magical morale effects.

• Pounce Attack (Level 7): When executing a Spring Leap directly into an attack, the Phraint gains $+2$ to hit and deals double damage on the initial strike.

• Hive Commander (Domain Level 9): Upon reaching 9th level, a Phraint may clear a hex and construct a subterranean or spire-like Hive-Fortress. Attracts $2d6 \times 10$ Phraint warriors (Level 1–2) and $1d4$ elite Phraint captains (Level 4–5) as a loyal garrison.