‘Heart of the Iron God’ Part 1 – Adventure for 13th-Level Characters

This was a third edition adventure in Dungeon Magazine #97 that was just too cool to pass up. Basically, a giant robot has risen out of the ocean with the goal to destroy a nearby town. This paired perfectly with a request I received recently from a Patron asking for a kaiju adventure. Instead, of totally building a new story (with maps, etc.) from the ground up, I figured–why not just convert this adventure? Furthermore, since it’s the level my PC’s are currently at, I’m probably going to run it myself.

Note: this is not my original property. I’ve only reposted content here for others to use the adventure. All of the original information is copyright of Paizo Publishing. I’d link to an official place for folks to download it, but it doesn’t seem to be for sale on DriveThruRPG or its affiliate sites.

Additionally, I had hoped to convert the entire file I have into a Word doc and just cut and paste. But Dungeon used some weird fonts which don’t read well with Adobe Acrobat Pro. Therefore, this is all retyped by hand. 

Spoilers: if you’re one of my players, don’t read this, because I’m going to beat you up with it next week. Thanks!

Heart of the Iron God

by Campbell Pentney

Artwork by Ramon Perez – Cartography by Robert Lee

‘Heart of the Iron God’ Index

“Heart of the Iron God” is a D&D adventure designed for four 13th-level characters. Those who survive should advance roughly 75% of the way to 14th level. A wizard capable of transportation magic would be particularly useful as would a stealth character such as a rogue. A character with high Intelligence will find many opportunities to gain unique knowledge and information.

This adventure uses the Greyhawk gods Heironeous and Erythnul, but any similar deities from your campaign could be substituted. The adventure can take place within any setting near a major coast.


Thousands of years ago, the god Heironeous aided his followers in the construction of a massive iron guardian known as the Colossus. This construction was a titanic, 185-foot tall statue created to defend the land from evil and malice. The Colossus was built with a habitable interior to allow followers of Heironeous to control basic mechanisms within the statue, while the soul of a selfless priest was bound within the structure itself to endow it with a living mind. The massive construct was an invincible force, and on numerous occasions defeated the evil that threatened to dominate the land.

So powerful was this creation that evil had no chance within the area and was forced to move on to darker lands. Occasionally a need for it arose once more, but mostly it spends years on end in a huge cavern, guarded by members of the church. The periods of time between uses of the construct lengthened, and eventually, evil uprisings were small enough that bringing out the Colossus wasn’t worth the effort. Priests eventually stopped tending to the thing, and when an earthquake collapsed the entrances to the cavern complex, few remained who even knew of the construct’s existence. Time passed and memories of the titanic defender passed into legend and myth.

Now, thousands of years later, the walls of the ancient cavern have been breached. The dark magician Xentarich, a man of cruel cunning and vast resources, was excavating earth from the region in order to create an underground fortress for his troops. He found the Colossus completely empty, and the spirit locked within its frame confused and bewildered. Taking advantage of the situation, he forged a pact with the church of Erythnul to allow the construct to be transported to a new, more convenient hiding place. The church also sent a priest to aid Xentarich (and watch the wizard’s activities), and a small battalion of warriors to act as a bodyguard. In exchange, the greedy Xentarich agreed to use the Colossus as an agent of destruction on behalf of Erythnul and his church, hiring a crew of eager gnome engineers to pilot and crew the construct.

Of course, to realize his plans, Xentarich had to trick the good spirit within the mind of the Colossus, insisting that he was an agent of the good gods who had been sent to rescue the Colossus from its prison for use as a weapon against the evil and “heretical” lands of the present day. Once this was accomplished, Xentarich used the Colossus to begin a campaign of mass devastation across the land, demanding huge ransoms from local barons and kings. These funds were then used to hire more crew to improve the inner workings of the Colossus. Once Xentarich’s own lands were subjugated, the wizards turned his attention to the rich and prosperous lands to the east. The Colossus was reinforced for underwater travel and cross ed the sea by striding along the ocean floor. It has now emerged in the PC’s homeland and has already caused severe destruction upon nearby coastal villages. The construct’s giant voice demanded an impossible ransom as it began a path of destruction toward the nearest large coastal city. So far no one has found a way to stop the device, and time runs short.


The characters have just left a town of your choice when the massive Colossus appears from over the horizon and tramples its way into a small village, causing massive damage. Smart adventurers notice it is on a direct path to a nearby coastal city. The characters have one day to prevent the Colossus from reaching the city. Close inspection reveals several small entrances leading inside the construct. The characters must penetrate the outer surface and enter the monstrosity. Once within they travel through the body of the Colossus while fighting off its crew and guards. Upon reaching Xentarich, they fight a deadly battle to halt his wicked plans. After this fight, they must convince the confused mind of the Colossus of their good intent and persuade it to stop the destruction. If they are successful, the Colossus begs to have its ancient life ended, pleading to the characters to destroy its heart. This frees the tortured spirit, yet the destruction causes a massive explosion within the construct, tearing its chest apart and sending it crashing to the earth.

Beginning the Adventure

When the characters first encounter the Colossus, read the following:

It is a brightly lit morning as you make your way along a rough dirt road, You take one last glimpse at the peaceful cluster of buildings behind you and turn to begin your journey. Suddenly you hear a faint noise, like a distant clap of thunder. The noise occurs again, then begins repeating regularly. You spot several puddles of rainwater flicker as the ground shakes in time with the noise. The booming grows louder, and you turn to face the cause of the noise. A giant metallic face appears over the horizon, humanoid in shape but with glowing red eyes. The figure draws closer and you catch your breath–such a creature must be nearly 200 feet tall! The colossal giant appears comprised entirely of steel and you hear what must be an echoing laugh issuing from its iron jaw. The creature is heading directly for the village and you can already hear screams of terror from the nearby populace. Although its intent seems clear, can the being even be stopped? As the creature draws nearer, you spot armored figures running near the giant feet of the giant figure, attacking several villages who have yet to flee. Then you see arrows arcing through the air and piercing villagers and livestock alike’ they seem to originate from the creature’s body.

A DC 23 Intelligence (History) check reveals the general history of the Colossus, but not how it was lost. The characters must act quickly, for the village will be trampled to kindling in 40 minutes. They begin the encounter 600 feet from the scene of carnage.

If the characters approach the village, they notice small fires have started and the Colossus is crushing buildings beneath its heavy iron feet. Hundreds of people flee in all directions, many of whom are cut down by arrows zipping through the air from above.

The characters might be noticed depending on their stealth and location. If they charge in immediately, the chaos and confusion hide them for a few minutes. The villages make little difference in the battle and flee as fast as they can. Make a (Wisdom) Perception check for the following groups.

Storm Hammers. Make Wisdom (Perception) checks with disadvantage, as they are distracted.

Darkblades and Nighthawks. The two archers in area 4 and the ballista crews in area 24 (90 feet up) might spot the characters. If the Darkblades see the characters, they start firing at them through the archery slits.

Gnome spotters. Two gnomes using a periscope viewer have orders to look for threats on the ground. Their viewers are 100 feet up and they warn the rest of the crew if the characters are spotted (this takes 2 rounds). Unless otherwise stated, gnome spotters are commoners.

Whether the characters are seen or not, after 3 rounds the hanger doors to area 13 open and four Nighthawks using gliders swoop around the Colossus for 4 rounds, attempting to spot and fire at anyone they see below (they start at an altitude of 120 feet, and descend 30 feet each round). After 4 rounds, they land and attack any survivors from the ground.

Should the characters be discovered by anyone other than the Storm Hammers, the alarm spreads around the Colossus. The Storm Hammers simply charge and attack.

If the characters don’t take steps to stop the attack, or they remain undetected, the village is decimated after 40 minutes, and the Storm Hammers return to area 11. If the Colossus is not stopped, it reaches a nearby major city in 24 hours and causes horrific damage before moving on. If the characters fled in terror in the initial encounter you might wish to have them hired by angry officials from the devastated city to try and find some weakness in the monstrosity. Otherwise, one week later a group of powerful wizards managers to enter and overcome the Colossus, although Xentarich escapes through the teleports in area 16.

Alarm! Alarm!

If at any time the characters are noticed trying to enter the Colossus, the crew attempts to sound the alarm at areas 14, 19, or 27 (it might take a round or two to reach an alarm). If this happens, all forces in the body section of the Colossus reinforce the auxiliary control room (area 14). Mercenaries in the hands and head section reinforce area 27 (including the shield guardian). After 10 minutes, these forces return to their positions on heightened alert for the next 12 hours. They receive a +5 bonus to passive Perception. Xentarich casts an auditory alarm spell on the stairs leading to area 27. Finally, the magic lift disks are switched off.

If the characters manage to enter the Colossus and word doesn’t reach the alerted forces they’re stopped within 5 minutes, Glymm assigns an available mercenary (preferably one of the gnome engineers from area 5) to monitor the museum (see area 18) and release the captive creatures there if invaders enter that room. Xentarich orders the Colossus toward the ocean and protects the control room with a wall of force. After 1 hour, the Colossus enters the ocean, flooding the body section.

Note that noise does not carry easily between the floors or walls (creatures make their Stealth checks with advantage while creatures have a -5 penalty to their passive Perception to hear).

If the main control room is taken over and gnomes are still present in the body section, they switch control to the auxiliary control room and continue to move the Colossus. If the characters take the control room and the crew and its defenders have taken roughly 50% casualties, the remaining crew (with the exception of Khrull and Torax) flee through the teleporter room (area 16).

View the bigger map by clicking here.


Getting Inside

The Colossus has eight levels, each containing small rooms and chambers populated by Xentarich’s hired mercenaries. Xentarich wishes to maintain the illusion of the Colossus as a giant living being, going so far as to use a magic item to project his voice from the mouth of the Colossus to issue threats and demands. Several entrances lead into the Colossus, each with different chances of being spotted. The DC to spot each entrance assumes the characters are on the ground; give them advantage to spot the entrances if they fly up to the level in which the entrance is built. If the PCs are more than 50 feet away, they have disadvantage.

A. Foot Entrances

Two small gateways blocked by portcullises are set into the front of the statue’s feet. The portals are simple to spot with a successful DC 15 Wisdom (Perception) check if the characters ever view the Colossus from the front. Any attempts at opening the portcullis might be frustrated by the fact that the feet are rarely on the ground for more than 10 seconds. The best bet to enter through the feet is when the Colossus first reaches the edge of the village, where it stops for 2 minutes while the gliders and archers attack the fleeing townsfolk. Beyond each portcullis, invaders can easily see the small winch in area 1. Each room is guarded by a small gnome. A charm or telekinesis spell could allow entrance here.

Portcullis. 2 in. thick; AC 19, 60 hp. DC 19 Strength check to force open or DC 19 Dexterity check using thieves’ tools DC 20 to pry open.

B. Trapdoor Entrance

A small iron trapdoor allows entrance between the legs of the Colossus. Spotting this portal is quite difficult requiring a DC 21 Wisdom (Perception) check and is impossible to open normally from the outside save for a knock spell or with incredible strength. The trapdoor is meant to be used as an exit only, so there is no mechanism for opening it from the outside. The trapdoor leads to area 2.

Iron Trapdoor. 1 inc. thick; AC 19, hp 40. DC 21 Strength check to break open.

C. Rear Door Entrance

A pair of concealed iron double doors allow access through the construct’s back. These portals are especially difficult to locate requiring a DC 18 Wisdom (Perception) check. Again, no exterior mechanism has been built to allow entrance to the Colossus here. The doors need to be forced with a knock spell or brute Strength. The double doors lead to area 13.

Rear Doors. 2 in. thick; AC 19, hp 60. DC 19 Strength check to break open.

D. Chimney

A tiny chimney located on the left shoulder of the Colossus is impossible to spot from the ground, but a character flying near the head can make a DC 20 Wisdom (Perception) check to notice it. A Small or smaller character can enter the shaft described in area 4, but only after first forcing the grate.

Grate. 1 in. thick; AC 15, hp 30. DC 15 Strength check to pry open.

Trap. The entrance is lined with brown mold to deter spies or assassins (DMG page 105).

E. Mouth and Eyes

Finally, an entrance was built in the mouth of the Colossus, which is extremely thick. The mouth is sometimes opened to issue commands or threats but it is currently closed. The glowing, red, crystal eyes of the Colossus are difficult to penetrate with weapons and serve as one-way windows allowing Xentarich to view the surrounding area. They have been enhanced with permanent true seeing spells that give anyone in the control room the benefits of that spell. Xentarich tries to dispel any flight magic on intruders should he become aware of them. Four arrow slits, one facing in each direction, give him a line of sight and allow him to cast spells on targets outside of the head.

Mouth: 1 ft. thick; AC 19, hp 360. DC 21 Strength check to break open.

Eyes: 1 ft. thick; AC 15, hp 120. DC 17 Strength check to break open.

Other Means of Entry

Entering the Colossus via magic is also possible. Dimension door allows access to the inside of the Colossus, but the interior is cramped and there is a 50% chance that characters using this spell appear inside a solid object. A disintegrate or passwall spell would also allow entrance into the construct. However, the construct is allowed a saving throw against either spell. Teleport would be difficult, as it requires an idea of the visual layout, and it isn’t possible to scry the inside of the Colossus. Arcane eye can’t be used to scout out the inside of the construct (due to its Divination immunity). A familiar or animal companion could scout a room and report back, but the teleport runs a high risk of misfiring.

Dungeon Features

The Colossus is a unique location to explore because it’s a vertical “dungeon” rather than the more typical, mostly horizontal locations the characters are used to traversing. All magical components of the Colossus (like the eyes) are powered by the heart stone within the chest of the Colossus and cease to work if separated.

The following features can be found throughout the construct.

Lighting. All areas within the Colossus are illuminated with enchanted ceiling tiles that glow and fade on command. They shed light as a torch.

Exterior Walls. The “skin” of the Colossus is 6-foot-thick, magically reinforced iron. AC 19, hp 2,160 (threshold 25). Immune to poison, psychic; bludgeoning, piercing, and slashing damage from nonmagical weapons.

Interior Walls, Floors, and Ceilings. All walls separating interior rooms are 1-foot-thick, magically enhanced iron. The rooms are consistently 13 feet high, separated from chambers on the next level by another 2 feet of iron. This prevents most any noise from passing through the floor to the level below or vice versa.

  • Interior Walls. 1 ft. thick; AC 19, hp 360 (threshold 20). DC 22 Strength check to break down.
  • Interior Floors/Ceilings. 2 ft. thick; AC 19, hp 720 (threshold 20). DC 26 Strength check to break.

Doors. All the doors within the Colossus are constructed of metal.

  • Steel Doors. 2 in. thick; AC 19, hp 60. DC 21 Strength check to break open.

Controls. The Colossus is operated by controls within the head. These manipulate the basic functions of the Colossus (like walking, stomping, and mouth movement). Such commands do not require the action of the spirit houses within the construct; it simply responds to stimuli provided from the command center. Complex actions, such as sitting or picking up an object, require the pilot of the Colossus to make a request of the spirit. The spirit can refuse such a command if it felt inclined to do so, but the spirit currently inhabiting the construct is confused and has yet to refuse such a request. In the event that the cleric’s soul “grows a spine,” Xentarich has had his gnome engineers rework the controls to override an action the spirit refuses. This would undoubtedly cause the mind of the priest to grow extremely agitated.

The Colossus’s Foot

Huge vehicle, (25 ft. by 25 ft.)

Creature Capacity 10 passengers

Cargo Capacity 1 ton

Travel Pace 8 miles per hour (192 miles per day)

Abilities Str 30 (+10), Dex 5 (-3), Con 19 (+4), Int 0, Wis 0, Cha 0

Damage Immunities poison psychic

Condition Immunities blinded, charmed, deafened, exhaustion, frightened, incapacitated, paralyzed, petrified, poisoned, prone, stunned, unconscious

Divination Immunity. The Colossus has been magically altered to prevent any Divination spell from penetrating its metal skin. Any such spells or magical effects that target a creature, object, or location within the Colossus automatically fail.


Armor Class 19

Hit Points 2,160 (damage threshold 25)


Stamp. The Colossus’s foot targets a point within 40 feet of it. Each creature within a 10-foot radius of that point must make a DC 27 Dexterity saving throw or take 28 (4d8 + 10) bludgeoning damage on a failed saving throw, or half as much damage on a successful one.

To be continued in ‘Heart of the Iron God‘ Part 2: Colossus Chambers 1 – 12


‘Heart of the Iron God’ Index

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