The Expanse RPG - a review


This review is based on:
• Reading the core rules through twice
• Reading the GM screen
• Generating a couple of characters
• Trying out the combat system with the six pregen characters from the The Ganymede Insurance Job.
• Running 2 published scenarios: To Sleep, Perchance to Dream (twice) and The Ganymede Insurance Job.
• And reading a third scenario (Salvage Op) and the first part of the Abzu’s Bounty mini campaign.
• My brother crunching some numbers for me, taking part in the combat tests and using his superpower (see below).

I like the Expanse books and I like the TV series. It is near future, hard science fiction which is a sub-genre I like. So it was pretty much a given I was going to fund the Kickstarter for the RPG. (Caveat: like most ‘hard’ SF, this means the authors put thought into the physics, astronomy and engineering – and if you are lucky also the chemistry and geology – but they just made handwavy bollocks up or grabbed some dubious trope from the 1930s whenever they talked about biology).

For those not familiar with The Expanse franchise, Earth and Mars are superpowers; corporations from both those nations have a lot of clout and get up to illegal and immoral things in the name of profit; and there is constant turmoil, gang warfare and sometimes outright rebellion amongst the downtrodden people of the asteroid belt and outer planets (the Belters). Most of the action will be on spaceships, space stations or asteroid colonies. There is no artificial gravity, so Martians are scrawny compared to Earthers, and Belters are scrawny compared to Martians. Guns fire bullets not laser beams. A ship’s drive can do high g burns to get from A to B on a plot friendly timescale of days to weeks, rather than months or years. The crew and passengers survive this body squishing acceleration by injecting a drug cocktail called the Juice. Or as my brother calls it: The magical drug of ignoring physics.

Character gen has both a random roll and a points buy system. Since I hate random roll chargen with a passion, the points buy system gets a gold star from me. Interestingly, if you use the points buy chargen, you can’t get either the unutterably terrible stat (minus 1 or minus 2) or the maxed out stat (4) which you can in the random rolls.

Chargen is fairly quick and simple. I will point out that if you have a specific character concept in mind, then you might want to do the stages in a different order from what the book says. I was trying to roll up a medic, got partway through and discovered that Lower Class (and Middle Class) folk cannot take Expert profession, which is what you need to do medicine. So pick the profession you want and work backwards from there.

Class in this game really means income bracket rather than the class system, but even so there are bits which make a Brit raise an eyebrow. Such as clergy being Lower Class and all military officers being Upper Class.

The art is nice. There are lots of examples to go with the game mechanics.

The Expanse uses the AGE system: 3d6 + Stat + 2 if you have the appropriate focus (which is sort of a skill), and try to beat a target number (usually 11). One of the d6 is the Drama Dice, which has various effects. For instance, rolling a double on any 2 of your 3 dice is effectively a critical: you get the Drama Dice’s value to spend as Stunt Points on a list of special effects. Such as extra damage, ignoring armour, getting an extra clue, storing up a lucky break to use later in the plot. Another Drama Dice effect is you run out of ammo if it rolls a six when you miss a ranged attack.

The AGE system says it doesn’t have hit points, but it sort of does. PCs and NPCs have Fortune Points. They are the critical resource in the game, because you use them to absorb damage (just like hit points), but you also spend them to turn a failed roll into a success, or to alter the value of a dice in order to give you a double.

Player Feedback
My players were divided on whether they liked the fortune point system. They liked spending them to create criticals and to turn failures into successes. They were less impressed with using the same bank of points as their hit points. And we did quickly notice that NPCs with a PC-like amount of fortune points take an awful lot of clobbering before the damage you are handing out has any game mechanical effect.

I think this moaning is more a narrative thing because the players were using guns. If they’d been punching each other in a bar brawl or doing a D&D style swordfight, then they may not have cared they had to hit a bad guy 10 times to make him fall over. But when they shot someone 5 times and he didn’t seem to notice, there was rather a lot of grumbling.

Most of the whinging (mine included) was variants on a theme: to take out the bad guys quickly, efficiently or in an action movie way, you HAVE to spend a hefty chunk of Stunt Points. But you mostly get Stunt Points randomly (you can generate a single Stunt Point as a major action) and you need 2 to 5 to do the James Bond type stuff. To take control of Stunt Point creation, the players have to spend shedloads of their Fortune Points to modify their dice rolls.

My players whinged, but on reflection I think this is deliberate game design. If you want to do a Knock Out Blow to every bad guy, you’ve got to accept that you’ll be spending Fortune Points like water. I’ll have to run this a bit more to get a feel for how the Fortune Point economy works.

Or fer frak sake! Put all the damn game mechanics in one section! Or if you insist on separate chapters for different bits, at least put all the combat mechanics in one place. Or have cross referenced page numbers prominently displayed in large friendly letters. Not everyone has the pdf and the Ctrl F function to hand during a game. Grr.
The game mechanics are scattered over:
• Chapter 1
• Chapter 5
• And the GM Section (Chapters 12 to 15).

Annoyingly, there are two pages of combat rules hidden in Chapter 12. This must be an AGE System/Green Ronin thing, because my copy of the Blue Rose RPG has the same inexplicable decision to hide the single most useful table (combat bonuses and penalties) in a chapter which is located after pages and pages of setting information. After 40 pages in the case of The Expanse, and after 200 pages of setting and GM advice in Blue Rose.

So I’m running a game, I’ve forgotten that those 2 pages are hidden at the back of the book. Cue lots of flipping back between chapters 1 and 5 and reading and re-reading things by me and a player, and scratching our heads and saying “How can they not have rules on penalties for shooting into melee?”. The confusion was not helped by the fact that the GM’s shield does not have the combat bonuses and penalties table on it!!! Bad RPG designer – no biscuit.

I know there is limited space on a GM screen, but I would gladly have sacrificed the “Things to remember about Hazards” text or the “Things to remember about Ability tests” text or some of the wordiness of The Churn or the Space Combat sections to have that combat bonus/penalty table. I can foresee a print-out and a piece of sellotape in my GM screen’s future.

Core Stunts
I had to ask the internet why some stunts are labelled “Core” as the rulebook didn’t say. Apparently those are the suggested stunts from each list and you are supposed to pick one of those when you can’t decide. Which leads neatly to…

Choice Paralysis – Too Many Stunts
There are just. Too. Many. Stunts.

All the games I ran were one offs. They ground to a halt whenever anyone got any stunt points to spend, because it takes ages to read through the list of options. Especially in combat, where there are 21 General Combat stunts, 8 Grapple stunts, 8 Melee stunts and 13 Gun stunts. You can use a general combat stunt when doing a grapple or melee or using a gun.

I’ve already made myself a cut-down list of combat stunts to use in con games, because there simply isn’t the time to let every player pore over the myriad options. In all fairness, the character sheet does have a “Preferred Stunt” section for players to write down the ones they like using. So in campaign play the choice paralysis may be less of a problem.

My youngest brother has a superpower: hand him any RPG book and it will fall open in his hands at the broken bit of the system. In the case of The Expanse, that broken bit is the Income system. Instead of keeping track of pounds and pence, there is an abstracted system. Each character has an Income score from -2 (horribly in debt) to 14+ (very rich). When you want to buy something, you look up its Income cost and then either you get it automatically (for costs up to your Income +4), or you have to roll 3d6 + your Income score with the item’s cost as the target number. If you buy stuff much higher than your Income bracket, it will deplete your Income score, because you are living beyond your means. So far, so good.

The broken bits are (a) the PCs getting paid at the end of a mission, and (b) the ability to generate infinite money.

The payment bit is broken because the scenarios say things like “This will increase everyone’s income by 1”. Since the income score is not linear it means at the end of the scenario, Baldrick the penniless peasant’s Income goes from 0 to 1 and he can now afford a hot meal and a blanket; whereas billionaire Bruce Wayne’s income has gone from 14 to 15 and he buys a fleet of new Lear jets and a diamond encrusted Batmobile.

The ability to generate infinite money is because you can sell things as well as buy them. This sale increases your income… and the maths doesn’t quite work the way the RPG authors (presumably) intended it to. So Baldrick (income 0) buys something which costs 3 and needs no dice roll to acquire. He can then sell it at a reduced price of 2 because it is second hand. However 2 is above his current Income (0), so his Income rises to 1! Or he can buy something more expensive. For instance, he can roll 3d6 and try to get an 8 to purchase something with cost 8. Pretty easy. If he then sells it for 7, that is 6 more than his original income of 0 so his income will go up by +2. A few more of these transactions and Baldrick will be as rich as Bruce Wayne…!

My brother also mentioned that there is an optimum time to buy expensive stuff. IIRC it was just before you level up, because living beyond your means reduces your Income, but levelling up restores it.

In Space No-one Can Hear You Admire the Topiary
Remember that combat penalties and bonuses table I mentioned above? It is exactly the same as the combat penalties and bonuses table in Blue Rose romantic fantasy RPG. Exactly the same. Which means:

  1. You are at -2 to hit someone hiding behind a hedge (light cover). The other don’t-really-sound-very-spacey things mentioned are rain, mud and heavy snow. Presumably you’ll be having a few battles in Avasarala’s garden or Holden’s parents’ farm back on Earth…? Or the GM will have to think of an excuse to have a gunfight during a methane rainstorm on Titan.
  2. Someone forgot to do some proofreading/continuity. So the values in that table (p192) rather make a nonsense of the values in the Cover Table (on p90 and on the GM screen). Nor do they quite tally with the Armour table on p76. Because in Blue Rose cover only gives you concealment, but in The Expanse it gives you concealment and armour bonuses.

• In Blue Rose, you are at -2 to shoot someone hiding behind a hedge.
• In the Expanse, you are at -2 to shoot someone hiding behind a space-hedge AND the space-hedge gives them +3 Armour.
• The light cover of a space-hedge is better armour (+3) than light body armour (+2). Space-hedges are tough!
• In fact, standing behind space-rain, space-mist or space-smoke is just as effective in armour terms as wearing light body armour.
• I think I will have to make my own table to use the common sense bits of all three of these tables.

I like this system enough to run it at cons or for one-off games for my regular players. I might run a mini-campaign of 3 or 4 sessions. I’m not sure I’d want to run a longer campaign, even with my fondness for The Expanse as a setting. I just have other systems I prefer for long term games.

EDIT: I’ve been trying to pull rules from disparate parts of the book into cheat sheets and have noticed something off with the gravity and acceleration rules. Gravity is divided into microgravity, low, normal, heavy and very heavy.

Taking Belters as an example: one set of rules (in chargen chapter and on p205) says Belters are fine at their native gravity (microgravity), and don’t mention anything occurring when they are 1 category above it (low gravity). They get the Hindered condition 2 categories above native (so in normal gravity), and are Restrained at 3 categories above (heavy gravity).

However, the rules on gravity (also on p205 but further down the page) say you may need Con rolls to avoid Fatigue at higher than your native gravity – and this starts as hourly rolls when you are 1 level above it (so in low-g for our Belter) and rises to one roll a minute when 2 categories above (normal gravity if a Belter). That’s far more punishing than what is suggested in chargen. If a Belter visits Mars even if his stat is maxed, he’s only been there less than a Martian day by the time the roll becomes impossible. Failure means he gets the Fatigued condition. The Fatigued rules say you can’t take a second Fatigued condition – so an hour later he gets the Exhausted condition. Then an hour later he gets the Helpless condition. In game mechanic terms, the Belter can no longer take any actions. (Unless this s a special instance of Fatigued where it doesn’t stack???).

So basically Belter characters can’t function anywhere except on ships travelling at a slower acceleration than the lowest mentioned in the travel tables (0.3g on p141) or on asteroids and space stations which have not been spun up to give them spin gravity. So Ceres is out (spin gravity of 0.3g), as is the Moon (0.16g) and Ganymede (0.15g). Which conflicts with canon from the books: Miller was a Belter who lived and worked on Ceres, for instance.

I’m wondering if there is a conflict between only wanting 3 categories in chargen (Belter, Martian and Earther) and the reality of the books/series that a metric tonne of characters don’t live in the Asteroid Belt, Mars or Earth? The Outer Planets Alliance gets its name from the fact that tons of its members live on Ganymede and a host of other moons. Many of which moons (according to the Expanse RPG rules) are low gravity, not microgravity.

I guess I can fix the conflict by either (a) moving the numbers so microgravity is 0 to 0.2g to include a bunch of those moons; or (b) saying ‘Belters’ can pick microgravity or low gravity as their home gravity.

Not sure what I do with the disagreement in the gravity/acceleration rules. Pick my favourite? Pick the one which annoys players the least?


Disclaimer: I really hated The Expanse book 3 and have stopped reading them, though I’ll probably catch up with the series at some point. The magic high-thrust high-impulse space drives which run off no known physics irk me, because this isn’t just “we don’t know how to build it”, it’s “we have absolutely no theory to suggest any possible way this could work” country not all that much closer to possibility than antigravity and warp drive.

Considering the clergy in book 3 they’re treated as Middle and Upper, as opposed to the ordinary working spacers who are definitely Lower.

3d6 + stat (of which 3 is pretty good) + focus (2) = 3d6+5 vs 11 = 95% chance of success for a pretty darn good person with the skill. OK, that seems not too terrible.

The odds of getting a pair of matching numbers in 3d6 are 96/216. 44% seems a bit common to call a “critical” but I’m a curmudgeon.

Abstract money systems are always a bit broken. I’ve tried building one off GURPS wealth levels and it hasn’t worked yet.


Tina is a fan of the series and has been playing the game for several months, clearly enjoying it. She has a very experienced GM and I suspect he’s fudging the few slightly broken aspects of the system. Green Ronin used a similar wealth mechanic in True20 and it hit the same sort of issues.

Personally I’ve never seen the show and haven’t read the books, despite having the first one sitting patiently in my Kindle library, but the other AGE RPGs seem pretty good, so I might give it a try one day.


Added an edit about the gravity/acceleration rules.

Meanwhile, I’ve had a re-read of bits of Blue Rose to compare and contrast.

  • Blue Rose doesn’t have Fortune Points, only hit points. They can’t modify their dice rolls as a matter of course (individual characters may eventually have special abilities which let them do it now and then).
  • A Blue Rose beginning character gets 21 to 40 hit points, whilst a beginning Expanse character gets 15 or 20 Fortune points. So they get less and have to do more with them.
  • The weapon damage in the Expanse is less granular than that of Blue Rose. The Expanse just has categories (e.g. all sword/sledgehammer ‘heavy close’ weapons do 2d6 + Str) whereas Blue Rose has different damage for lance, axe, sword, two-handed sword, etc.
  • Blue Rose crossbows do the same damage as Expanse pistols: 2d6 + Perception.
  • Blue Rose two-handed axes and two-handed swords do the same damage as Expanse rifles (3d6) but with a Str bonus instead of a Per bonus.


Eeek! If someone attempted to spin Ceres up to 0.3g of spin “gravity” at its equator, it will have disintegrated early in the process. Spin “gravity” pulls outwards, not inwards. Its own gravity is only 0.029g, just under a tenth of the claimed spin gravity. There’s no way it has the structural strength to withstand this treatment, since it’s made of rock and ice, with a density of under 2.2, and has collapsed into a spherical shape under its own gravity


From book 1 Leviathan Wakes:

Ceres, the port city of the Belt and the outer planets, boasted two hundred fifty kilometers in diameter, tens of thousands of kilometers of tunnels in layer on layer on layer. Spinning it up to 0.3 g had taken the best minds at Tycho Manufacturing half a generation, and they were still pretty smug about it.

I think I had vaguely assumed a Cole habitat (aka bubble world), where the asteroid is cored, filled with water or something else volatile, then melted by solar mirrors to inflate it. (Particularly since that’s what Larry Niven did in Known Space, and The Expanse clearly owes a lot to that.) But “tens of thousands of kilometers of tunnels” doesn’t sound like that.


I suspect that the idea with clergy - given that “class” is really “income” - is that they don’t have huge amounts of disposable income, and can’t go bankrolling spaceships or whatever. Except that the books include influential big-name TV preacher types who are clearly living pretty well…


Well, quite; in Abaddon’s Gate we have Anna Volovodov, who’s catering primarily to manual labourers when we first meet her, but we also have Hector Cortez, “close personal friend and spiritual advisor to the secretary-general himself”.


Well, Ceres is approximately 940km in diameter, which doesn’t fit either. It could, I suppose, be a stupidly huge space station along the style of a von Braun torus, mounted on the dwarf planet Ceres via some gigantic bearings. But the gyroscopic effects of Ceres’ rotation would be horrible, and Ceres’ gravity is enough to make things awkward. It would be easier to build a space station nearby and mine Ceres for materials. I think this has to go in the “sloppy research by the author” box.


Ceres rotates in nine hours or so. Could you anchor a cable at the equator, extend it past Cererosynchronous rotation, and put an 0.3 gee habitat in a gondola? 80 000 km of cable ought to do it.


That make some sense, but it will be a swine to dock with. You need to be able to sustain 0.3g in a forced orbit, plus some more thrust for maneuvering. Not an attractive requirement for a commercial hub, when anyone can set up a near-zero-g port on a small asteroid. You also have to worry about plastic deformation of Ceres, given the pull on the cable.

Edit: I’m not trying to be nasty to the Expanse, but the brokenness of the ideas is jumping out at me and screaming.


They also talk about “down near the port, where the spin gravity was strongest” but I’ve already had that argument with Dr Bob. :slight_smile:

I think the basic problem is that they wanted to do hard SF without… hmm. OK, Daniel Abraham has a B.Sc. from New Mexico, though I don’t know in what specifically; I don’t know about Ty Franck’s background. I was going to say, “without being scientists”; the thing was originally intended to be the setting for an MMORPG so I imagine spectacle was always high on the priority list.


Well, I’ve long doubted that that could possibly produce a material sufficiently free from defects as to have significant tensile strength. It turns out that you need a great deal of tensile strength to pull off a Bernal sphere or Oberth cylinder. And that’s even supposing that you had a mix of stony and nickel-iron material to work with. Ceres is frozen mud.


I suspect that the (possibly subconscious) thinking is that Anna is a protagonist character (one could almost say “player character” – there are times when one can really tell that these books were written by gamers), and hence the character generation system should allow people to come up with similar characters. Hector is more of an antagonist and an obstacle; gamers aren’t expected to play someone like him, so his stats can be determined arbitrarily.

Or, allowing more choice of styles of play – if Hector is a PC, he’s been through a series of scenarios which raised his income level, and hence eventually his Class.


I think I’ve heard – I could be wrong – that it was derived from what was originally a d20 Future campaign. Which probably says all you need to know about where it’ll lie on the SF Mohs Scale.

(Note: I don’t entirely agree with the TV Tropes scale there. I have my own idea about the inevitable decay of SF concept hardness, in which fanatically hard SF authors borrow only from science papers, other authors borrow from them, a third generation borrows from the second, and so on, until “hyperspace” or “gene editing” have decayed by a process of Chinese whispers from scientific terminology to magic words. On that principle, The Expanse is about one full generation further along the scale than, say, Transhuman Space. Which makes the TV series about three generations harder than most TV SF.)


The feeling I get (as someone who’s designed a few SF settings) is that they started off thinking “hard SF” and then noticed just how blasted long it takes to get anywhere with any plausible or even theoretical space drive, so they handwaved that, and then they needed Belters, and they didn’t read Pournelle’s piece from 1974 (“Those Pesky Belters and Their Torchships”) which makes it clear that if you have a civilisation based in “the Belt” rather than on just one rock it has plenty of delta-V for going to Earth and Mars too, and… basically every time science clashed with ADVENTURE!, science lost.

Which is not the worst thing to do if you want an action series, and as you say it’s still a lot better than most TV SF.


I think I’ve heard – I could be wrong – that it was derived from what was originally a d20 Future campaign. Which probably says all you need to know about where it’ll lie on the SF Mohs Scale .

But, but, but… the Mohs Scale runs from 1 to 10! Does that mean there are SF books which are harder than reality??? :slight_smile:

Yes, this! Plus the original authors were (a) writing in 1968 so borrowing from something written in 1967 and (b) only read astronomy and physics papers, not from biology or geology or oceanography papers.

LIke the Belters are tall and thin. No, no, no. Thin yes. Tall, no, Biology doesn’t work that way.


I think the assumption for Niven’s Belters and other low-G types was “the more work growing tall is, the less of it you’ll do, and therefore vice versa”. Which is I think not entirely unreasonable in the 1960s.


I think even in the 60s a biologist would have pointed out that if a normal leg bone is 10 cm x 2 cm x 2 cm, and a low g bone is 40 cm x 1 cm x 1 cm, it uses up exactly the same amount of material. And is therefore not less work to manufacture.

Or they’d point out stuff about lever length and mechanical advantage, and if you make the limbs too long you’ll have to make bigger muscles to compensate for the reduced mechanical advantage.