OSR: The Flame Pomerium Part 2: Giant Mecha Fights in the GLOG

Back in this post, I proposed that giant mecha fights could be easily run in most D&D-like games without changing any of the rules. All you need to do is change the scale.

Mortal Scale: the usual human scale.
Bulwark Scale: the giant mecha scale. 50x larger, but none of the values change. 

If you have to interact between the Mortal Scale and the bulwark scale, use 50x as the multiplier. A Bulwark-sized dagger deals 50d6 damage to a mortal-scale goblin (assuming you can hit the darn thing). A mortal-scale archer deals 1d6/50 damage to a Bulwark.

Rounds take the same amount of time if you're using Pacific Rim -> Evangelion scale. If you're going for a slower, naval-type-battle approach, Bulwark rounds take 5 Mortal rounds.

Village, Pene Men

Here are 3 options for running a Giant Mecha-based game:

1. One Mecha, Multiple PCs
The classic "starship" layout. One PC drives, one PC operates the guns, etc. 
Pros: group cohesion, investment in common welfare.
Cons: "we've already fired the wand-cannon so you get to do nothing for the rest of the fight."

2. Multiple Mechas, One Per PC
The classic "group of high school kids save the world in an animated TV show" layout.
Pros: customized mechas, more feel of control, no one is left "idle".
Cons: less group cohesion, multiple mechas can solve problems more easily, more repair time.

3. Multiple Mechas, One Per PC, NPC crew
The classic "starship" layout, but with NPCs in most roles.
Pros: customized mechas, team uniforms, rivalries, and internal politics
Cons: more for the GM to track, traits can be diluted or flanderized by the squad structure

I like Option 3 the best.

Test: the GLOG

Let's see how many edits I need to make. I've rolled up a usual mortal-scale character: Rolf, the Human Fighter. I now want to roll up Rolf's Bulwark.

The usual order is:

1. Race
2. Stats
3. Class
4. Background, Estate,
5. Starting Gear

1. Race

Right off the bat, our usual Race table isn't going to work. Luckily, it can very easily be adapted to a Chassis table:
Roll Chassis Reroll Bonus Penalty
1 Simian STR +2 to STR for inventory slots Take 2 turns to ready a ranged weapon or spell
2 Lithe DEX Can fold into 1/4 usual space Attacks throw you 2x as far
3 Fortress CON Attacks throw you 1/2 as far -2 to Wisdom for Initiative
4 Striker STR Jump 2x as high Cannot use heavy weapons
5 Scout DEX Can see 2x as far as normal Critical hits automatically knock you prone
6 Flanker CHA Move over all terrain with no penalties Take 2 turns to stand up from prone
It's trivial to add more. These are just examples.

Rolf's Bulwark is a (5) Scout. 

2. Stats

No changes here. Rolf generates the following:
STR: 13

DEX :10 or 14 -> 14
CON: 11
INT: uses Rolf's stat -> 12
WIS: uses Rolf's stat -> 9
CHA: 10


HP: 7

3. Class

Rolf's Bulkwark is a Scout Wizard, because Wizard seems like the most difficult class to adapt.

We're going to replace "Spellbook" with "Magical Recharge Hangar", "Scroll" with "Rolled-Up Disposable Drum of Parchment Slotted Into the Main Reactor" and "Wand" with "Magic Cannon".

Rolf needs to select a wizard school. Many of the schools are simple to adapt, so let's pick the most difficult: Animist Wizards


1. Transform into a creature an agglomeration of black ooze, wood, and flesh with your a hideous tormented face that has either (a) a fly speed of twice 2x Movement, (b) 3x Movement (c) swim speed of 2x Movement, (d) burrow speed of Movement, (e) the ability to squeeze through gaps smaller than a human the bulwark's head. Choose one option at character creation. The transformation lasts for 1hr per Animist Wizard template per day.

Rolf's Bulwark has a dangerous "beast-mode" button (the beast, in this case, being Nago). Using it probably blights the land forever, induces existential angst, and scares the hell out of everyone. He selects (a). His Bulwark can fly.
2. Dim or extinguish all non-magical light sources within 10’ 500'.

Useful for hiding a village.
3. Touch someone to learn if they have killed another sentient creature in the last 24hrs.

Not really applicable, although it might be useful for inter-team drama if he has to pick someone up and discovers that their sweet, innocent, NPC friend has killed recently.


Rolf rolls a 2 and a 5

2. Telekinetic Shove
R: 50' 2,500‘ T: creature or object D: 0
An object or creature within range is hurled through the air. Save to negate. A human Bulwark-sized creature travels 10’ 500' per [dice], and takes 1d6 damage for every 10' 500' traveled. A creature thrown at another creature requires an Attack roll to hit and inflicts 1d6 damage for every 10' 500' traveled. This spell will also blow open all the closed but unlocked doors in a room, shatter all the windows in a building, or knock the thatched roof off a peasant's shack.

5. Sleep
R: 50' 2,500' T: [sum] HD of Bulwark-scale creatures D: 10 min / permanent
Target falls into a magical slumber, and can't be awoken by anything less vigorous than a slap (a standard action). Non-alert, unaware targets are not allowed a Save. If [sum] is at least 4 times the creature's HD, the duration becomes permanent (until slapped) and the creature no longer needs to eat or drink while sleeping. If you also invested 3 [dice] or more into this spell, the duration becomes permanent, and you can set the only condition that will cause the creature to awake (the sunrise before the apocalypse, true love’s kiss, etc.)

Do not require adaptation. Some mutations can be repaired (healed).

Require minimal adjustment; fix as needed, invent all sorts of horrible nonsense.

4. Background

If I was actually running this game, I'd make up a world, generate background tables, etc.

But here's the background of Rolf's Bulwark. Its name is Desperate Measures.

It would stand 300' high, but it crouches like a sprinter most of the time. Its frame is wicker and bone. Humanoid, with a cat-skull head. Luminous eyes, red, dark. Beneath the wicker, muscles of rope and chain, thick layers of tar. The pilot sits in the head. Unlike other Bulwarks it needs no other crew. The thing itself is alive.

When it is dormant, its black heart beats slowly, once every 10 minutes. The tar cools and solidifies. The eyes grow dim. It twitches and dreams. To wake it, feed a living sacrifice into the furnace-heart. The sacrifice must be unwilling. That was how the witches built it. Draw the ashes from the fire, mix them with pitch, spread it on the Bulwark's wounds. Build the fire higher - it burns not wood, but souls. Add fledgling birds, incense, rare books. Stoke the fire. Then, the Bulwark awakes.

It spits spells from its mouth like curses. It can put a Great Beast to sleep and slit its throat. It can also put a village to sleep, to spare them the horror of death. With a flick of its clawed finger, it can send a ravening monster tumbling through the air. It can also fly, on unfolding wings that drip black ooze and poison the water. That was how the witches built it, how they were asked to build it. In a sensible age, their monstrous child would have been burnt and condemned. Now, it defends all civilization.

Rolf is a sensible man, a loyal man, untutored in the arts of wizards, unambitious, devout, and battle-tested. He was chosen to pilot Desperate Measures because he, of all people, would never turn on mankind. He can resist the witches' charms. He will not forget who he is, half-buried in the Bulwark's head, steering it by intent and half-gestures.

5. Starting Gear

We've replaced the wizard starting gear earlier. A starting character usually has some money to spend. For convenience, Rolf's Bulwark also has the same money, but can only buy Bulwark-scale items.

Rolf buys a lantern (oil-lamps in the eyes behind crystal-glass lenses, can project 1,500' cones of light if he widens the eye-slits fully, has enough fuel for an hour) and two daggers (claws).

Rolf also rolls up the rest of his crew: 3 NPCs who see to the maintenance of his war-machine. You can use the Table of Camp Followers to get a starting point, or any number of other online generators.

1. Grisbelda: witch, Animist Wizard, horribly old and bent, cunning, afraid of love, afraid of death, and (behind all the murder and the callous use of life), devoted to the Cause. Doesn't actually have a scheme; constantly accused of having a scheme.

2. Welfrida: witch, apprentice Animist Wizard, slightly too innocent for her own good, always on the edge of doing something stupid and idealistic like raising a dead friend through dodgy rituals or saving a sacrifice.

3. Gemthar, diplomat, obvious spy from the Capital. Here to keep an eye on Rolf and the Witches, kill them all if they start getting ideas. Quite transparent about this. Uses this to lull the others into a false sense of security. He will pretend he is not their friend, while dropping hints that he deeply cares for them. He does not. This is another trick.
Wood Robot, nancynismo

Other PCs

The Balfontaine Triplets are 3 Biomancers who fuse together to form a hideous flesh-Bulwark, a Simian Fighter.

Thodric the Just commands a Fortress Knight, a true shield against the apocalypse. His Bulwark is more conventional, crewed by his servants, repaired by his peasants, powered by magic, pulleys, and counterweights.

Haspar is an elf and commands a Bulwark of living wood, a Striker Fighter, who uses a bow taller than a cathedral and arrows made from dozens of trees. 

Other Changes

The Death and Dismemberment Table for Bulwarks needs a few edits. Bulwarks with Fatal Wounds do not fall unconscious. Fatal Wounds use the same rules, but cannot be doctored in combat. Any failed Fatal Wounds (not removed after 3 turns) go into a separate pool. When the number of failed Fatal Wounds = the Bulwarks level, the Bulwark stops functioning.

Lethal Damage also blows through to the PCs. If a Bulwark is knocked from 1 HP to -4 HP, everyone inside takes 1d6+4 damage. This might be increased or decreased depending on the attack and the location of the crew.

A week of repair fixes any one Injury and restores the Bulwark to full HP. Bulwarks can be repaired from almost any disastrous injuries. Ox-cart teams or allied dragons will haul limbs back to town.


Since gp=xp no longer works for this type of game, I'd use (HD of Giant Beast x 10 = equivalent xp). Killing a 1 HD giant goblin gets you 10xp. Everyone who actively participated in the kill gets the same xp. You also get bonus xp for saving civilians.

Total Edits

1. New Table of Races
2. Renaming bits from the Wizard Class
3. Multiplying ranges by 50x
4. Inventing New Follower/NPC tables
5. Death and Dismemberment changes
6. Leveling and XP alteration.

That's it, really. Not bad at all!

Next up, testing this system on Lamentations of the Flame Princess. Cannons! Woo!


  1. Two comments:

    I saw the link to this post and the first thing I did was bookmark it. Not even read it.

    Skerples, you complete me.

  2. I think you could make some small changes to combat in order to make the 'one Mecha, multiple PCs' more of a tactical, involved process. Limit turning for the pilot, only allow the gunner to attach forward, and let the engineer do things like repair damaged systems or change the load out. Although for pure simplicity, making as few system changes as possible, the NPC crew method is probably best.

    1. Yeah, I'd worry that would still end up with the "gunner does X every turn" problem. If it's optimal for the engineer to roll Int. to repair every turn, that's all they do. No tactics, just rolling. It's that or build a complex system of potential actions for each role... but the whole point was to make it simple.