Yearly Archives: 2018

Catastrophe magic

This is a magic system I have been testing. It is general enough that I think it should be easy to use with other traditional fantasy games, if you like, given a small amount of adjustment to the system you are using.

This is a roll to cast system. You need to decide on a set of known or prepared spells for a character. Then, the die outcome will take care of the resource aspect of spells. You also need a resolution system that provides five levels of outcome. You can think about these outcomes as levels of player character success or as augury into the fictional world. The five outcomes are:

  1. Principle intensified
  2. Principle
  3. Principle & corollary
  4. Corollary & decline
  5. Catastrophe & decline

The principle is the basic spell effect, the thing that the sorcerer is generally attempting to bring about. The principle intensified is the critical hit version of this. The corollary is an unintended side effect that generally complicates the magician’s life but may occasionally be useful. Decline represents a decrease in future spell potential or magical energy. The simplest implementation of decline is, following a Vancian approach, forgetting the spell. And finally, catastrophe is a total misfire which may have personally deleterious effects. This set of outcomes means that something magical always happens but the potential corollaries and catastrophes should make players think twice about playing with arcane fire.

To resolve the casting of a spell, I use an ability check, similar to the approach described here, with intelligence for black magic and wisdom for white magic.

For an approach closer to classic d20, consider the following:

Let target = 10 + spell level. Then, roll 1d20 and add spell bonus (something like one-half level, rounded up). Interpret the result as follows:

  • Natural 20: principle intensified
  • Target + 4: principle
  • Target: principle & corollary
  • Below target: corollary & decline
  • Natural 1: catastrophe

Further, you need a way to determine what each class of outcome means for a given spell. Writing new spells with extensive corollary and catastrophe tables is wonderful but by no means necessary.

Ideally, catastrophes are specific to individual spells, but lacking specific catastrophes, you can fall back to some general outcomes, such as these:

(I am sure there are others available too.)

Hacking a spell to support this system can be easy. For example, here’s a hack for the classic spell magic missile:

  • Principle intensified: +1 extra missile
  • Principle: as written
  • Corollary: an additional missile targets something non-animate (determine randomly)
  • Catastrophe: determine target of each missile randomly (friends and foes)

For many spells, it is feasible to rule on potential corollaries and catastrophes in real time. I would just clarify with the player what the potential scope of outcomes would be and confirm intention to cast the spell prior to the roll.

See also:

Text versus culture

I contend that one of the major causes of misunderstanding in discussions of tabletop roleplaying games is differential prioritization of where rules should live. At base, games are bundles of practices that can be stored and communicated in various ways. For example, baseball in the United States started as a game played by amateurs using informal rules that lacked textual basis. A social club wrote the first baseball text in 1845: the Knickerbocker Rules. Tabletop roleplaying game rules can also reside ultimately in culture or in texts.

The community that developed around the Forge in the early 2000s is one influential example of prioritizing texts. The games developed by designers from the Forge and the subsequent Story Games forum tend to have clear, explicit procedures and written creative agendas. Critique often focused on potential disconnect between what a game text promises, either explicitly or implicitly, and what the game delivers. For example, Vampire: The Masquerade promised “struggle for humanity” but “always ended up as emo superheroes” (ref). This disconnect tends to be framed as a flaw or a sign of broken rules. In this tradition, to understand games one returns to the original text, tries to follow the procedures carefully, and then evaluates the outcome. For example, here is Luke Crane on Moldvay D&D and Ron Edwards, quite recently, on 4E D&D. A different community that exhibits strong textual fundamentalism in a different way is the portion of Pathfinder players concerned heavily with tactical game balance and character build optimization.

In contrast, some tabletop roleplaying game traditions deemphasize singular texts and are more likely to prioritize norms and expectations communicated informally. The community that developed around the old school renaissance seems closer to this approach on balance. People seem perfectly comfortable with a more distributed storage of practices, drawing from resources such as the old school primer, assorted blog posts, and recalled experiences. In this approach, no single text contains the full game and various aspects may lack textual basis completely. This is not just house rules, where players modify a canonical text to suit local group preferences, though house ruling is a part of how rules evolve culturally. Instead, the full game is more like a cultural tradition rather than a solid, defined, bounded artifact.

In terms of game design, both approaches have pros and cons. A strong textual basis serves as a shared landmark. People or groups that differ in expectations but share a specific, relatively explicit text, such as Apocalypse World, Pathfinder, or 5E D&D, might be able to communicate more effectively compared to people that lack such shared singular text, all else equal. Culture, however, is extraordinarily effective in social coordination, requiring little explicit deliberation to function. For example, norms are more influential in directly coordinating social behavior than laws, and when laws do come into play, few people other than judges and lawyers are familiar with legal details.

The major misunderstanding, as far as I can tell, is the idea that the choice is between system and individuals making things up rather than between prioritizing text and prioritizing culture. For example, in a classic Forge document, Ron Edwards writes, to characterize an objection to the importance of well-designed systems: “It doesn’t really matter what system is used. A game is only as good as the people who play it, and any system can work given the right GM and players.” And, from a DIY D&D perspective: “sometimes people just suck and redesigning the game won’t fix that” and “Reading the book is not and never should be essential.” Now, of course there is also an effect both of well-crafted procedure in text and individual creativity, but players (and cultures of players in aggregate) can differ on preference for textual versus cultural embodiment of rules.

Personally, I see the benefit of both approaches. I spend a lot of effort trying to effectively proceduralize rules that I develop, particularly for many of the less fluent aspects of traditional fantasy games, such as encumbrance, resource management, and bookkeeping, with the Hazard System being a more involved application of this kind of thinking. However, insisting that individual texts be highly pedagogical and entirely self-contained both creates strangely unmoored documents, seemingly unaware of their likely audience, and ignores the massive, brilliant social fabric to which we all belong.

That said, this post is more about facilitating communication than advocating for a particular approach to game design. People with a strong focused design bent might want to consider that games can be stored culturally, similarly to the way traditions develop and propagate more broadly. And, people who feel like they already know how to play and just want the text to get out of their way may find that trying to play some innovative or experimental games may suggest new techniques or even be enjoyable as completely self-contained games. At the very least, recognizing that people may differ on this preference might help prevent misunderstanding.

Credit to a post by Dan M. that helped me crystalize this idea and provided some useful language.

See also: game design as common law, though that post concerns a method to craft rules in the context of a particular group, rather than broader cultures of gaming.

Mettle, trauma, and grit

For me, the ideal hit point or vitality system for tabletop roleplaying games involves the constant threat of engaging consequences while also mitigating the disastrous influence of luck. Using OD&D and sticking to the three little brown booklets comes close to this ideal when run in a certain manner, but still perhaps gives luck too much influence at first level and creates too much of a hit point buffer at mid to high level. Put another way, I want a system that encourages players to always care about combat consequences but rarely if ever shanks without warning. And, of course, the system must be fluent, easy to use, plugged in to the core flow of play, and require minimal bookkeeping.

Playing Kingdom Death gave me some ideas regarding ways to build a combat system that better prioritizes these goals, and that influence should be clear in the following sketch. As written, it may be too invasive to just trivially drop into a game using a B/X type engine, especially given that it requires replacing traditional armor class with ablative armor, but I think it would be possible.

Before anyone gets all up in my business about the dynamics of real armor or wounds, I want to emphasize that realism is a relatively low priority apart from maintaining predictable fictional consequences, necessary for allowing creative problem solving. Instead, the point is to create rules that facilitate choices and consequences while reinforcing the overall feel of the kind of survival fantasy that is my preferred mode for tabletop roleplaying games. This system assumes the turn structure of the Hazard System.

Section of the Hexagram character record sheet relevant to armor and mettle


Rather than hit points, player characters have mettle, which can be both bound to hit locations (all player characters have this kind of mettle) or floating (for tougher characters, those with high constitution). Instead of taking damage, player characters mark mettle boxes. The hit locations are head, body, abdomen, arms, and legs. Each location has two points of mettle except the head, which has one point. Additionally, player characters have a number of floating mettle points equal to the constitution modifier. These points can absorb damage to any hit location.


Currently, Hexagram uses active defending—blocking or dodging—sort of like this, rather than resolving monster attack rolls versus player character armor class. The details of the monster attack step are less central to the mettle and trauma system, and any method to decide if an opponent hits a player character in combat should slot in fine here. Even just leveraging the saving throw system seems like it would be a totally functional system for determining whether a character risks taking some damage, bringing armor, mettle, and so forth into play.


Player characters can equip pieces of armor to any hit location. Armor is ablative, meaning that it reduces incoming damage. The protection offered by a piece of armor maps roughly to the traditional light, medium, heavy (or leather, chain, plate) scale with light armor offering 1 point of protection, medium offering 2 points, and heavy offering 3. Since player characters have five hit location slots, they can mix and match, for example by wearing a heavy visored helmet but a light, boiled leather breastplate. Equipped armor still takes a gear slot, so piling on protection comes at the cost of lower versatility. Additionally, player characters act at a disadvantage when wearing armor with protection higher than the strength bonus.


When a player character takes damage, determine hit location randomly, subtract armor protection from damage taken (minimum zero), and then mark off one mettle slot for each point of damage remaining. I assume that the magnitude of damage is generally around 1d6 (following OD&D flat damage). If at any point a player character takes damage and has no remaining relevant mettle, then the character is in danger and must roll for peril. This is the step that can potentially lead to serious consequences, including character death.

Hit location (1d6): 1 head, 2 legs, 3 arms, 4 abdomen, 5-6 body

Peril (1d6): 1 messy death, 2-3 bleeding, 4-5 fracture, 6 sprain

Fractures disable the affected hit location. For example, a character with a fractured arm can no longer effectively wield a weapon using that arm. Healing fractures requires magic or taking a haven turn to recover (which would require retreating from a dungeon to town). Sprains work similarly but player characters can recover from a sprain by resting for a single dungeon turn (so, in effect, sprains only influence the current combat).

Other than being messy, gaining the first bleeding condition has no direct result. However, getting the bleeding result again, even to another hit location, means the character bleeds out and dies.


Injuries are tricky to handle well in tabletop RPGs. On the one hand, they can make characters much less fun to play even for players on board with working out the implications of player character hardship. On the other hand, a fictional consequence is almost always more engaging than simple HP attrition through both adding narrative color—fan of blood—and changing the context as appropriate—a tiled floor slippery with blood. Further, while permanently changing settings and characters through play is satisfying, ruining characters is generally not. You can’t lose an arm in Dark Souls, and if you did I imagine the common response would be to restart the game. That would be a hardcore lose condition. For this reason, the peril table includes immediate fictional consequences beyond something like HP loss, such as heavy bleeding or broken bones, but defers the possibility of permanent disfigurement, the control of which falls to players through the grit system, described below.


Bleeding and fractures count as trauma, and surviving trauma strengthens tough characters. Player characters that survive a trauma can mark a grit box during recovery in a haven. Characters have a number of grit boxes equal to the constitution modifier. When a player marks a grit box, they should note how the trauma has permanently marked the character. This could be a scar or something else, and is entirely up to the player, but should be fictionally appropriate to the particular trauma (this would be a good place to insert fantasy prosthetics if such are setting-appropriate, such as necromantic grafts or enchanted wooden limbs). In effect, grit slots are like unlockable extra mettle slots.

False Machine has some creative ideas for scars here.


This system feels mechanically quite perilous. A mettle slot is roughly equivalent to one hit point, meaning that on average marking 1d6 mettle slots (expected value: 3.5) results in peril for all hit locations lacking armor. However, five-sixths (83%) of peril results are non-fatal initially. Strictly speaking, a one-shot kill is still possible, but is statistically much less common than the OD&D case of 1d6 damage versus 1d6 HP, and could easily be entirely eliminated if desired (such as by changing the messy death result to unconscious and dying, with final death occurring at the end of combat lacking miraculous intervention). Also, the odds improve dramatically with some armor while still maintaining the threat of real consequences.

In terms of complexity creep, this system requires an extra roll to determine hit location if an opponent hit is successful. So, there is a small increase in complexity, but the overhead seems minimal, which I have confirmed in preliminary play testing. The peril step replaces what I would otherwise run as a saving throw versus death, and that is an uncommon occurrence. Tracking the mettle and hit location slots does require a little help from the character sheet, but that seems manageable (see the character record sheet excerpt above).

Zines for megadungeons

(Being a review of Megadungeon #1, among other things.)

Since rediscovering fantasy roleplaying games sometime around 2011, I have followed the development of several home brew megadungeons. Some of my favorites include the taking-OD&D-seriously Dwimmermount, the Lovecraft-by-way-of-Vikings Black City, the Diablo-infused “precious shithole hellscape” Nightwick Abbey, the steam-age demonic fantasy cruise-ship-as-megadungeon HMS Apollyon, and the gleeful toybox-filled deity-haunted dungeon Numenhalla. These projects remain mostly unpublished1, present only as referee-musings, map-fragments, or, travelogue-style, as scattered session reports.

Numenhalla, however, is finally seeing (gradual) publication in the recent Hack & Slash zine Megadungeon, of which two issues are available as of this writing. This post considers Megadungeon #1, which contains a mix of referee advice, setting glimpses, some player-facing rules, and a couple intro dungeon areas. First, I will cover what I consider weaknesses, along with a few observations. Then, I will cover strengths and the promise Megadungeon (the zine) has for the practice of developing megadungeons for play.

The presentation has several weaknesses, the primary being transitions. Many of the sections began life as a blog posts, and it shows. This is only a minor flaw; in some ways, it even adds to the utility, creating a series of self-contained easy to reference nuggets, but it also makes the whole feel more like a grab bag than a carefully designed book. The amount of actual dungeon content in this issue is also rather small. While the two dungeon areas are wonderfully evocative, with beautifully hand-illustrated maps, they are also somewhat linear and detail only 15 keyed areas (dungeon content arguably occupies 5 of the 38-some zine pages). While I think it is a common mistake to attempt keying a giant sprawl of rooms when starting a megadungeon, rather than working with a more tractable map, I was still hoping for a bit more. That said, the creativity of the areas makes up somewhat for the quantity, and I realize that issue one also may involve more setting and play advice groundwork compared to future issues.

Crop from page 8

The biggest strength, apart from the obvious enthusiasm, is the art, which projects a sense of playfulness that is too often lacking in fantasy art. However, the playfulness never descends into explicit goofiness or self-deprecation, and at some points almost verges into a sense of the mystic (a good thing when attempting to capture the fantastic). The dungeon features themselves are often weighted with promise (see the pitch black door, for example). I have less to say about the various rules bits, such as the augatic class (a tin man style robot that gains new powers through upgrades), but they are well done and easy enough to drop into any game using a B/X type engine.

Though the last handful of years has produced several notable published megadungeons2, such as Stonehell, Barrowmaze, Castle Gargantua, and Maze of the Blue Medusa, I would still like to see more experimentation in different ways to present a megadungeon for direct use by someone that is not the dungeon’s author. To my knowledge, no existing megadungeon has used a zine format so I am curious to see where Courtney takes this. The closest approach I am aware of is the collaborative darkness beneath megadungeon published in the now-defunct Fight On!. Though there were a few standout levels, such as Sham’s level 2 and level 3, it suffered overall from a lack of coherent vision.

The zine format encourages zone-level publication, which naturally breaks down the task into more achievable units. While this might be less of a concern for Numenhalla, as I gather a large portion of the dungeon is already designed, it would probably be a good approach for any referee who wants to share their megadungeon. The major challenge using this form is that a good dungeon contains relationships between various areas, and this is difficult to pull off if one creates and publishes areas in sequences. How does one include a well-considered gate to level 5 in level 1 if level 5 is as yet undefined? Notably, the Numenhalla entrance halls do contain several (locked) connections to deeper areas, but we will need to wait for future issues to see if the dungeon can make good on this promise. 

Anyone interested in the idea of megadungeon play would probably get something out of this zine. As the text states:

Numenhalla lies beneath all cities,
All mounts and valleys,
And all lands.

As a disclaimer, I have gamed with Courtney both as player and referee. As with all my reviews, I attempt to review impartially, and always buy everything I review, never accepting review copies.

1. The ACKS-published extrapolation of Dwimmermount is the closest to publication for any of these dungeons, but ultimately completes a different project than the original idea behind Dwimmermount.

2. I make no attempt here to offer a comprehensive list of recent megadungeons, but the ones I listed stand out as attempts to push the form in various ways.

Considering short campaigns

Apocalypse World agendas (2nd edition, page 80)

In my experience, people tend to play tabletop roleplaying games as either one-shots or with the expectation of a perpetual, extended campaign. I have thought off and on about running games aimed explicitly at a midpoint between these extremes. The television analogue here would be the mini-series. Something like True Detective season 1 or a self-contained anime series like Gargantia on the Verdurous Planet.

The challenge would be to serve the agenda of play to find out what happens while also drawing the set of sessions to a close in a way that is satisfying. That is, how can one ensure the freedom necessary for fulfilling exploratory play while avoiding the mirror-image dangers of aimlessness and railroading?

Here is a first pass at how I might think about setting up such a mini-series game. First, determine a handful (say, three) of questions regarding the fictional situation, for which an answer (any answer) would constitute a satisfying arc outcome. Maybe one of these could explicitly be a win/lose condition, as in some tournament modules, but that seems like the easy way out. Then, lay these questions out explicitly before play so the players are in on the particular enigmas. Second, gear preparation entirely toward the details around the enigmas.

If other priorities emerge through play, or players end up more interested in other, unpredicted conflicts, that would be fine too. In my experience though, imminent uncertainty provides gravitation even without any other mechanical support, so just having a few big unanswered questions, such as the outcome of whether an invasion is averted diplomatically or by force of arms, may be sufficient. I might also consider something like building XP reward into advancing a countdown clock, but probably only after trying to run a something like this using an approach resting only on shaping player expectations.

Finally, it seems reasonable to work with the assumption that while some or most such mini-series arcs may connect to nothing else, they also may be continued in subsequent seasons if everyone is enthusiastic, allowing characters to sometimes persist. To have integrity, one would need to sometimes follow through on the promise of continuity, otherwise I suspect everyone would revert to mentality more characteristic of one-shots, which would not quite reach the potential I see for this kind of play. Depending on the particular rules, Flailsnails would be another reasonable approach, but that only works for some types of games.

Halfway houses

Most traditional resolution procedures are binary. For example:

  • Attack roll: either hit (inflict damage) or miss (often boring)
  • Saving throw: either success (maintain status quo) or failure (disaster)

This approach is simple and works well enough most of the time, especially at low levels where the damage from a single hit can make a big difference and missing can build tension, but can sometimes lead to boring slogs when results are chains of misses and the influence of any single action is low.

An alternative approach is to add an intermediate degree of success incorporating unintended consequences and complications into intermediate results. The Apocalypse World 2d6 +stat roll is one method like this that is easy to use:

  • 10+ = success
  • 7-9 = mixed
  • 1-6 = it gets worse

This works well but does have a few potential downsides. Using 2d6 means limited scope for adjustment, as +1 makes a big difference and each additional bonus makes an even bigger marginal difference. Consider (probabilities are approximate, taken from Anydice):

  • 10+ = success (17%)
  • 7-9 = mixed (41%)
  • 1-6 = it gets worse (42%)

Bonuses translated into effective probabilities are:

  • 2d6+1 yields 28% it gets worse, 44% mixed, 28% success.
  • 2d6+2 yields 17% it gets worse, 41% mixed, 42% success.
  • 2d6+3 yields 8% it gets worse, 34% mixed, 58% success.

While this might seem okay if you like to keep numerical inflation to a minimum anyways, it does, somewhat counterintuitively, make the marginal bonus (the next potential +1) always more influential, in terms of mechanical effectiveness, than the last +1.

2d6 is also incompatible directly with d20 systems.

It is easy enough to create a similar method using 1d20 though, and such yields a uniform distribution, meaning that each marginal +1 has the same impact on resulting probability (+5%).

Here is one approach which has some attractive properties:

  • 19-20 success (10%)
  • 10-18 mixed (45%)
  • 1-9 it gets worse (45%)

Single digits = bad is easy to remember; 19 or higher = extra good is also easy to remember. The outcome ranges could easily interoperate with standard ability or attack bonuses. Bonus increments correspond to 5% probability adjustments, which are easy to reason about.

This differs slightly from the approach taken by the traditional attack roll and similar resolution systems, where the roll, modified by properties of a character such as attack bonus, must attain a threshold determined by some external factor, such as armor class. In contrast, the Apocalypse Word target numbers (and these adapted d20 target numbers) are fixed. If the only modifiers to the roll are character properties such as ability score bonuses or attack bonuses, then this resolution mechanism is essentially solipsistic; the result is unaffected by things external to the character.

This could be an issue if you want success versus a dragon to be less likely than success versus a goblin. Using situational penalties could address this problem, but that way lies the hassle of adding and subtracting a host of potential bonuses or penalties. Used sparingly this works well enough, though it is less than ideal, and anyone that has played Pathfinder or even something like traditional AD&D should be familiar with modifier creep (1d20 + strength bonus + attack bonus + magical weapon bonus – odious magical aura penalty … and so forth). It works mathematically of course, but can be a mess.

Here is another approach, using tiers based on academic letter grades for shorthand:

  • 19-20 = A
  • 16-18 = B
  • 10-15 = C
  • 2-9 = D
  • 1 = F

This adds some complexity at first glance, but also supports slightly more granular outcomes that are also relatively easy to remember, especially 1 = F. The only threshold without an easy to remember association is the transition between C and B results, occurring at 16. Further, now it becomes easy to see how the tiers of this solipsistic resolution system could correspond to properties of a fictional world, if desired, without needing to worry about setting difficulty classes by challenge. For example, results of C hit unarmored opponents, results of B hit lightly armored opponents, and results of A hit heavily armored opponents. More generally, C = easy, B = moderate, and A = hard, assuming easy tasks still represent an uncertain outcome that is potentially consequential either way (otherwise why bother rolling at all?). Or: C = success with setbacks, B = success, and A = extraordinary success.

Ultimately, a graduated outcome like Apocalypse World is probably more interesting than succeed/fail systems (heresy?), so I am tempted to interpreting the roll as follows:

  • 19-20 A = extraordinary success/critical hit/overkill
  • 16-18 B = success
  • 10-15 C = success with complications
  • 2-9 D = it gets worse
  • 1 F = it gets much worse/catastrophe

What about the dragon > goblin issue described above? One could also model this difference through hit point totals and the severity of complications.

This set of outcomes is less sensitive to bonus inflation than 2d6 +stat but would still break with Pathfinder-scale bonuses of +15, so some consideration of bounded accuracy would still be required. Basically, just keep bonuses from growing too large. +10 means that a character would always be at least in the success with complications tier apart from the 5% chance of rolling a natural 1, assuming conventional interpretation of natural 1 results.

1-10-16-19 seems easy enough to remember and has the potential to be universal, applicable to anything that one might normally resolve by rolling a d20. I think I may give this a shot the next time I run something.