You don’t need to master the minutia of a setting to run an amazing game in it! But you don’t want to get flippant with continuity. What you’re looking for is the grok threshold, and this video has the tips you need to get there!

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Go to Part 1

To check for encounters, roll 1d12 once per watch.

A roll of 1 indicates that an encounter should be rolled on the hexcrawl’s wandering encounter table.

A roll of 12 indicates that the characters have encountered a keyed location within the hex as an exploration encounter. Most hexes only have a single keyed location. For hexes with multiple keyed locations, determine the location encountered randomly.

Playtest Tip: It’s often effective to do an encounter check for all of the watches in a day simultaneously by rolling 6d12. (See Fistfuls of Dice for tips on interpreting simultaneous dice rolls.)

Exploration Encounter: Exploration encounters only occur during watches in which the characters are traveling or otherwise exploring an area. They do not occur during watches in which the characters are resting or otherwise stationary.

Wandering Encounter: A wandering encounter can occur during any watch. (They are usually creatures, whose movement can bring them into contact with the expedition regardless of whether the expedition is on the move or not.)

Note: See Hexcrawl Tool: Spot Distances for guidelines on the distance at which initial Wisdom (Perception) and Dexterity (Stealth) checks should be resolved.

ADVANCED RULE: ENCOUNTER CHANCE

You can vary the probability of having an encounter. The table below shows the probability per watch of different encounter checks and also the chance per day that there will be at least one encounter.

You also need to determine whether or not a keyed location has been encountered. This can be done in one of three ways:

• Determine it on the same encounter die. (The probability does not have to match the probability of a location encounter. For example, you might roll 1d8, triggering a wandering encounter on a roll of 1 or 2 and triggering a location encounter on a roll of 8.)
• Roll a separate encounter die. (This can have the advantage of simultaneously triggering both an encounter and the keyed location, suggesting that the encounter might happen at the location.)
• Roll a single encounter check and then check to see if that encounter is the keyed location. (You might build this onto the random encounter table – i.e., results 1-10 on a d20 table might be for the keyed location while 11-20 have the wandering encounters. However, this can make it difficult to modify the encounter table or use different encounter tables while keeping the probability of finding locations consistent.)

Note that if you’re using some of the advanced rules below that interpret certain wandering encounters as exploration encounters, these will effectively reduce the odds of an encounter happening.

ADVANCED RULE: LOCATION PROPERTIES

Keyed locations may have optional properties that determine how and when they’re encountered.

On Road/River/Trail: The location is on a road, river, or trail. Expeditions traveling along the road, river, or trail will automatically encounter the location (unless it’s hidden, see below). Expeditions avoiding the road, river, or trail will usually not encounter the location.

Visible: The location is large enough or tall enough to be seen anywhere within the hex. Expeditions entering the hex automatically spot the location. If a rating is given (e.g., Visible 2), then the location can be seen from that many hexes away.

Hidden: The location is difficult to spot. When this encounter is generated, make a second encounter check. If an encounter is not indicated on the second check, the location has not actually been found. (If the expedition is in exploration mode, they may instead make a Wisdom (Perception) or Intelligence (Investigation) check to locate a hidden location after the first encounter check.)

ADVANCED RULE: % LAIR

The percentage listed is the chance that a creature encountered as a wandering encounter is instead encountered in their lair. If the creature is encountered in their lair, the encounter is considered an exploration encounter.

Note: This check functionally generates a new location for the current hex (the lair of the indicated creature type). Over time and thru play, therefore, this encounter system will continue to add new content to your hex key (helping to fill the vast, howling emptiness of a typical hex). The more time the PCs spend in a particular area, the more content will be added to that area.

ADVANCED RULE: % TRACKS

The percentage listed is the chance that a creature’s tracks are encountered (and not the creature itself). Tracks are only found as an exploration encounter.

The tracks may be followed using the Tracker watch action. Tracks are usually 1d10 days old. DMs can determine where the tracks lead (although they’ll usually circle back to the creature’s lair in both directions). See Hexcrawl Tool: Tracks for additional guidance.

Note: When generating a wandering encounter, check to see if the encounter is tracks. If it is not, then check to see if it’s a lair. If it is not, then it’s a wandering encounter. Once again, notice that these additional checks will substantially reduce the odds of a night time encounter (when the party is not on the move).

ADVANCED RULE: BORDER ENCOUNTERS

This percentage, which is listed for either a region or a specific hex (or set of hexes), is the chance in a hex bordering on a different region that the wandering encounter should be rolled on that region’s encounter tables.

This rule is obviously only relevant if you have different wandering encounter tables customized for each region.

ADVANCED RULE: ENCOUNTER REACTION CHECK

To randomly determine a creature’s initial reaction to an encounter, roll 2d6 on the following table.

Obviously, the roll is not necessary if you already know the creature’s attitude. After the initial interaction, assuming hostilities don’t immediately break out, you can use Charisma checks to determine if the creature’s attitude improves, worsens, or stays roughly the same.

Note: The outcome of the reaction table is deliberately vague. This is necessary because it can be applied to a wide variety of intelligent, semi-intelligent, and unintelligent creatures, but it’s also expected that the DM will use their creativity and knowledge of the setting to make the general result something specific. A Hostile encounter, for example, might be a group of starving wolves; slavers looking to capture the PCs; or a group of paladins who mistakenly think the PCs are the slavers.

ADVANCED RULE: SIMULTANEOUS ENCOUNTERS

It can be desirable for your encounter procedures to potentially generate multiple encounters in the same watch:

• It creates uncertainty for the players. (They can’t simply assume that they won’t experience another encounter in the current watch because they’ve already had one.)
• It can create a dynamic fluctuation in difficulty.
• The combination of multiple encounters into a single encounter can create lots of different encounters from a relatively simple encounter table. (Are the two encounters allies? In conflict with each other? Is one encounter drawn to the sounds of the PCs dealing with the other encounter? If you generate one encounter at the lair of a different encounter, what are they doing there? And so forth.)

There a few methods you can use for achieving this:

• Make multiple checks per watch.
• On a successful encounter check, immediately make a second encounter check. (You can repeat this again if the second encounter check is successful, potentially putting no limit to the number of encounters possible in a single watch.)
• Incorporate a “Roll Again Twice” or similar entry on your wandering encounter table.

Each method has its own advantages and disadvantages.

Note: I, personally, check for a second encounter when the first encounter is successful. This second encounter check might indicate the keyed location of the hex, placing the first encounter there.

ADVANCED RULE: CIRCUMSTANCE DIE

The circumstances of an encounter will be informed by the terrain type, time of day, spot distance, watch actions, and so forth. (Generating an encounter with eight kenku at night while the expedition is resting on the open plains suggests a very different encounter than one with eight kenku in the middle of the day in a dark forest.)

When a particular condition is either pervasive in a region or important to the campaign (but should not be present in every single encounter), a circumstance die can be used to randomly incorporate it.

Examples could include:

• An Icewind Dale campaign in which there’s a 2 in 6 chance for an encounter to occur during blizzard conditions.
• A 1 in 4 chance that the demon trapped in a cage formed from one of the PCs’ souls attempts to assert control.
• A 1 in 6 chance that the encounter is being watched by a strange, shadowy figure with glowing red eyes.
• A 1 in 6 chance that the creatures encountered belong to or are working for the Countess Remorzstan (with appropriate brands or work papers).
• A 1 in 8 chance that the encounter occurs near an outcropping of glowing purple crystals.

Some such conditions might, under other circumstances, be generated through other procedures. (For example, blizzards might be generated through a random weather table.)

EXAMPLE: SAMPLE ENCOUNTER TABLES

Location Check: 1 in 1d6

Encounter Check: 1 in 1d10

Border Encounter: 1 in 1d20

Note: I indicate hexes which are already keyed as potential lairs for this creature type. This can inform the nature of wandering encounters and/or suggest a potential origin/terminus for tracks.

This table uses several advanced rules. When rolling an encounter, I would simultaneously roll a 1d6, 1d10, and 1d20 for each watch.

If the 1d6 result is a 1 (indicating a location encounter), it would indicate that the PCs have found the keyed location in the hex. If I’m not using simultaneous encounters, I would then ignore the other dice rolls (the location check “overrides” them; you could also just roll the 1d6, then the 1d10, then the 1d20, but that’s not necessary and is more time-consuming).

If the 1d10 check indicates an encounter, then you’d check the 1d20 roll to see which encounter table you should be rolling on. (You could also theoretically roll 2d20 of different colors, allowing you to immediately identify what type of encounter.)

With an encounter identified, you would then check % Lair, % Tracks, and # Appearing (although you don’t need to check for tracks if a lair encounter is indicated). Lairs and tracks are also exploration encounters, so if those are indicated when the party is resting, you can treat the encounter check as having no result and the watch passes quietly.

This is, of course, a fairly complicated example featuring a lot of the advanced rules all being used simultaneously. For a much simpler resolution you could just roll 1d12 (1 = wandering encounter, 12 = location encounter), roll 1d20 on the wandering encounter table (if a wandering encounter is indicated), and then the number of creatures appearing.

DESIGN NOTE: PROCEDURAL vs. DESIGNED ENCOUNTERS

A procedural encounter will usually generate one or more general elements. (For example, 1d6 friendly orcs.) As described in Breathing Life Into the Wandering Monster, the expectation is that the DM will contextualize this encounter. In other words, the procedural encounter is an improv prompt for the DM to create the encounter (often combined with a simulationist element of modeling, for example, what kinds of monsters lurk in the Darkovian Woods).

A designed encounter, on the other hand, is far more specific: You’re essentially prepping the material that you would improvise with a procedural encounter.

The Principles of Smart Prep maintain that you generally shouldn’t prep material that can be just as easily improvised at the table, so generally speaking I would describe most designed encounters as being training wheels for DMs who aren’t confident improvising encounters from procedural prompts yet. (There can be a number of exceptions to this, but they’re pretty rare in actual practice, in my experience.)

In other words, designed encounter tables typically result in a lot of wasted prep. They also get used up (a procedural encounter can be used over and over and over again to varying results; a designed encounter is specific and generally can’t be repeated). This creates gaps in your encounter table and a need to frequently restock them.

(Procedural-based encounter tables will also need to be tweaked or restocked from time to time – if the PCs wipe out the goblin village, it may result in no further encounters with goblins – but this is very rare in comparison.)

DESIGN NOTE: SETTING LAIR/TRACK PERCENTAGES

In designing your encounter tables, the % Lair and % Tracks values can be set arbitrarily. For a quick rule of thumb, use Lair 20% (or Nil for animals that don’t really have lairs) and Tracks 40%.

Older editions actually included values for one or both of these stats in their monster entries, so for some creatures you may be able to reference those older resources.

A gamist tip here is to increase the % Tracks value based on difficulty: If there’s a monster that’s a lot more powerful than everything else in the region, crank up the % Tracks so that the PCs are more likely to become aware that it’s there than they are to run into it blindly.

A simulationist tip is to vary both numbers by a sense of the creature’s behavior. Here’s an easy example: How likely is a flying creature to leave tracks compared to a woolly mammoth? (See Hexcrawl Tool: Tracks for thoughts on what types of tracks a flying creature would leave.) You can also think about how much time a creature spends in its lair and use that as a guideline. (They spend about half the day in their lair? 50%.)

A dramatist tip is to think about how interesting each type of encounter is for each creature type. Is a ghoul lair more interesting than running into a pack of ghouls in the wild? If so, crank up the ghoul’s % Lair.

The last thing to consider is that, as noted above, a Lair encounter will generally add a new location to the current hex. The higher you set the % Lair values on your encounter tables, the more often this will happen and the quicker areas of your campaign world will fill up with procedurally generated points of interest.

Conversely, how comfortable are you improvising this type of content? It’s good to stretch your creative muscles, but it may make more sense to keep the % Lair value low until you’ve gotten more comfortable with pulling lairs out of your hat.

Go to Part 6: Watch Checklist

The awesome thing about failure in roleplaying games is that it provokes creativity, heightens the stakes, and drives the adventure in interesting directions.

I would even go so far as to say that an adventure without meaningful failure is, all other things being equal, inherently worse than one with it.

Unfortunately, this may not be immediately obvious if you’re used to scenarios prepped as plots (i.e., a predetermined sequence of events). In a scenario prepped as a plot – particularly if the GM is using railroading to enforce that plot – there is only one path. And if there is only one path, any failure must be interpreted as temporary and, therefore, meaningless.

Failure is meaningful (and interesting) when it creates an obstacle or consequences, and therefore requires the creation of a new path.

Once again, if you’re used to prepping and running plots, this can sound incredibly daunting: With a plot you have to figure out how to reliably route the PCs from Scene A to Scene B. That’s non-trivial and if the pre-planned routing fails, improvising an alternate route on-the-fly is tough.

But if you’re prepping situations instead of plots, then the pre-planned route doesn’t exist. And if the pre-planned route doesn’t exist (or isn’t important), then it’s not even your job as the GM to come up with the alternate route! It’s the players’ job.

Despite this, though, you may find that failure is still just causing the wheels of the game to spin. Why?

Well, another common way in which failure can become meaningless is when unnecessary action checks are being resolved. As described in The Art of Rulings, action checks should generally only be made when failure is either interesting, meaningful, or both.

If you’re a beginning GM trying to figure out how to make failure meaningful, here’s a couple of simple techniques that you should be able to rely on.

INTRO TECHNIQUE #1: NO RETRIES

The easiest way to implement meaningful failure is to simply not allow retries: If you failed to pick the lock on the door, that failed check tells us that you’ll never be able to pick that lock. You did your best; it didn’t work.

Now what?

Kick it in? Cast a spell? Look for a different entrance? Look for a key? Seduce the housekeeper? I dunno. You tell me.

But as you can see from these example alternatives, each of these new paths creates interest: The PCs are leaving evidence or engaging in further exploration or creating new relationships. Arguably all of these are, in fact, more interesting than if they had simply picked the lock and gone through the door.

Note: A trap that you can fall into here is thinking, “Well, if failure is better, then I should just force everything to be a failure!” There’s a longer discussion to be had on this point, but the short version is: Success is also important if, for no other reason, than that the players will become increasingly frustrated if they can never actually accomplish anything. So let the dice fall where they may.

To be clear, this technique is not the be-all or end-all of how to adjudicate failure. There are more advanced or gradated techniques that can be used to good effect with practice. But if you’re just getting started, you don’t have to make it complicated.

INTRO TECHNIQUE #2: QUICK-AND-DIRTY FAILING FORWARD

Okay, so you’ve done that for a few sessions and you’re starting to get a feel for what meaningful failure looks like in actual play, but you’re also starting to chafe a little bit under the straitjacket of never allowing retries.

You’re ready to make it a little complicated.

What we’re going to use here is a technique called failing forward: The mechanical result of failure (e.g., rolling below the target number) is described as being a success-with-complications in the game world.

A simple rule of thumb for when you should use failing forward is whenever disallowing a retry feels a little weird to you: Why can’t the PC just try to pick the lock again?

In our first technique, the intended path fails and the PCs need to find an alternative path. Failing forward is a different way of making failure meaningful because you don’t annihilate the intended route (whether you prepped it or the players chose it). You just complicate it.

Coming up with interesting complications on-the-fly, though, can feel intimidating. So, when in doubt, just impose a cost: You succeed, but…

• You have to pay extra.
• You took damage.
• Your equipment broke.
• It took extra time (if that’s relevant).
• Someone knows you did it who you didn’t want to know.

If you have a better idea, great. But if not, these five broad categories can cover like 90% of fail forward checks. In fact, you’ll usually have multiple options. When picking a lock, for example:

• You open the door, but trigger the security trap. (You take damage.)
• You open the door, but your lockpick snapped off in the lock. (Your equipment broke.)
• You open the door, but it took twenty minutes and now you only have ten minutes before the Count returns home. (It took extra time and it was relevant.)

If nothing works and you can’t think of something outside the box, that’s fine: Either don’t make the check in the first place (just let them automatically succeed) or default back to no-retries-allowed and move forward.

Advanced Tip: You can get a little fancy here with a fortune in the middle technique by offering the cost to the player. For example, “You’ve almost got the lock open, but the hacked security camera is going to come back online. Do you stay and open the door or GTFO before the camera spots you?”

INTRO TECHNIQUE #3: BASIC PROGRESS CLOCK

A progress clock is a simple, visual way of tracking how close a particular outcome is to happening. There are a lot of different ways that you can use a progress clock, but for today, when the PCs fail their first check during an endeavor (e.g., sneaking into mansion, tracking a band of orcs, investigating a cult’s activities in Dweredell):

1. Create a progress clock by drawing a circle and dividing it into four, six, or eight parts.
2. Set a significant consequence or overall fail condition. (For example, security at the mansion realizes there are intruders and the alarm is raised, the PCs lose the trail of the orcs and can no longer follow them, or the cultists succeed in summoning a demon who begins rampaging though the Great Market).)
3. Whenever the PCs fail a relevant check, fill in one part of the progress clock.
4. When the progress clock is filled, trigger the consequence or fail condition.

This technique can be used with any type of action check, but for our purposes primarily provides a default consequence for failing forward: If you can’t think of any other consequences, just fill in the next section of the progress clock and explain the connection.

Progress clocks can exist in one of three states at that table:

• Open Clock: When you create the clock or fill in a section, you show it to the players. This is often the easiest method, making it crystal clear what the consequences of a failed check are with no fuss.
• Hidden Progress: When you create a clock, you directly or indirectly tell the players that it exists. (For example, when they’re sneaking into a mansion you can clearly state that there’s a risk the security team will detect them.) But the clock itself remains hidden. The players don’t know how large the clock is or exactly what the progress on the clock is. However, because the clock’s progress is hidden from them, you will need to clearly communicate the consequences of failure to them. (For example, if they fail forward on a lockpicking check, you might describe how they managed to get the door open, but they’ve left clear signs of tampering that might be noticed. Such explanations, you’ll note, will also inform exactly how the failure condition plays out – in this case, it’s possible that the alarm is sounded because someone noticed the damaged lock.)
• Secret Clock: You create the clock without telling the players it exists; it serves strictly as a tool for you to keep track of things. As with a hidden progress clock, it’s your responsibility to continue clearly communicating the consequences of failure to the players in your description of the game world.

Advanced Tip #1: Other events or actions can fill in sections of the progress clock even if there isn’t a failed check. If something happens that logically moves events closer to the progress clock’s outcome, fill in a section. (Similarly, particularly terrible failures might fill in more than one section at a time.)

Advanced Tip #2: It’s also possible for progress clocks to “run backwards.” If the PCs do something that sets back the plans of the cult, for example, it may make sense to erase one of the filled sections of the progress clocks. (On a similar note, progress clocks are not inevitable: If the PCs break into the mansion and get out before filling the progress clock, the alarm doesn’t sound. If they wipe out the cult, the demon is never summoned. And so forth.)

Go to Table of Contents

This is the DM’s map for running the Avernian hexcrawl. It’s designed for use with the Alexandrian Hexcrawl, as described in the 5E Hexcrawl series. We’ll be making some tweaks to this structure, however, to accommodate the unusual features of Avernus.

HEX SCALE

1 Hex = 40 miles (center to center / side to side) = 23 mile sides = 1385 square miles

The Avernian Hexcrawl uses 40 mile hexes. When tracking progress, this means it requires 20 miles of progress to exit a hex through one of the two nearest faces. (If they exit back through the face through which they entered the hex for a reason other than doubling back along their own trail, it requires 2d10 miles of progress to exit the hex, unless circumstances suggest some other figure.)

Design Note: The primary reason for choosing a 40 mile scale is because the PCs are likely to end up using infernal machines with much higher speeds of travel. The secondary reason is aesthetic: Avernus is supposed to be a wasteland. By increasing the scale of the hexes, we achieve that (increasing the average distance between points of interest).

OPPRESSIVE ENVIRONMENT

The conditions in Avernus are debilitating, alien, and severe, particularly for mortals. In addition to the normal encounter check, there is a 1 in 6 chance per watch that an oppressive condition will begin. Once begun, an oppressive condition continues until another 1 in 6 check per watch ends the effect.

EXTREME HEAT: Temperatures reach extreme heat. A creature exposed to extreme heat must succeed on a Constitution saving throw at the end of each hour or gain one level of exhaustion. The DC is 5 for the first hour and increases by 1 for each additional hour. Creatures wearing medium or heavy armor, or clad in heavy clothing, have disadvantage on the saving throw. Creatures with resistance or immunity to fire damage automatically succeed on the saving throw, as do creatures native to Avernus. A successful saving throw while resting resets the DC to 5.

CHOKING MIASMA: Thick, noxious fumes fill the air. They may have a source (like volcanic clouds rolling off the mountains) or they may seem to rise from the ground or even just spontaneously emerge from the air itself. At the end of each watch, creatures must succeed on a DC 15 Constitution saving throw or suffer one level of exhaustion. Creatures who are resting gain advantage on the saving throw. Creatures with resistance or immunity to poison automatically succeed on the saving throw, as do creatures native to Avernus.

PSYCHIC EVIL: The supernatural evil of the Nine Hells weighs on the bodies and souls of those who are not evil. A non-evil creature must make a DC 15 Constitution saving throw at the end of each watch or suffer 1d3 points of psychic damage.

ACID RAIN: Thick purple clouds spatter the plains with burning acid. A creature without shelter suffers 1d6 acid damage per hour.

RAIN OF STONE: Small meteors pelt the plane. Creatures without shelter must succeed on a DC 12 Constitution saving throw each watch or suffer 1d6 bludgeoning damage per hour. There is a 1 in 10 chance per watch that the meteor storm intensifies, with blazing orbs of fire plummeting from the sky. Creatures without shelter must succeed on a DC 15 saving throw or suffer 5d6 fire damage and 5d6 bludgeoning damage.

TERRAIN CONDITION: Each type of Avernian terrain has an oppressive condition. This result on the table indicates that you should use the oppressive condition of the terrain in the expedition’s current hex.

As noted below, some terrain conditions do not persist. They occur once in the watch during which they are rolled, and then additional checks for oppressive conditions immediately resume in the next watch.

AVERNIAN TERRAIN

The wasteland of Avernus is scattered with rocks of obsidian and quartz. There’re mountains dotting the bloody-dusty plain, and foothills march across the land like the overturned tracks of some gargantuan, unknown beast. – Planes of Law (1995)

ASHLANDS: The ground here is covered in a thick layer of black ash, generally varying in depth form six to eighteen inches. The ash does not easily compress or support weight, so travelers will often find themselves more or less wading through the ash.

Oppressive Condition – Ash Pit: In some areas the thin layer of ash is much deeper than it appears. Sentinels can attempt a DC 18 Wisdom (Perception) check to spot the ash pit as the expedition approaches. If no one spots the ash pit, 1d4 random characters in the expedition must make a DC 15 Dexterity saving throw or abruptly sink 2d4 feet deep in the ash.

At the start of each ash-bound creature’s turn, they sink another 1d4 feet into the ash. A character can attempt to escape by using their action to make a Strength check with a DC equal to 10 plus the number of feet they’ve sunk into the ash. If they have become completely submerged, they suffer disadvantage on this check and also begin suffocating.

Ash pits do not persist as an oppressive condition.

BONE BRAMBLES: A maze of warped trees and bonelike vines. Calcified corpses merge with the trees, covered in fungal pods that feed on the blood oozing through the undergrowth. Experienced Avernian explorers know that bone brambles often grow up around sources of fresh water.

Oppressive Condition – White Mists: The brambles exude a thick, cloying, almost oily white mist. This creates a condition of poor visibility (halving moving speeds and giving disadvantage on navigation and forage checks). The mist is almost refreshingly cool by Avernian standards, but there are strange whispers and disturbing groans that come and go among the mists.

CAUSTIC BOGS: On the current map, the caustic bogs are formed from the polluted run-off from Bel’s Forge (Hex H2), but similar areas can be found across Avernus, horrific remnants of the Blood War.

While travelling through the caustic bogs, characters must succeed on a DC 12 Constitution saving throw each watch or gain the Poisoned condition. The character can repeat the saving throw every 24 hours, ending the effect on itself on a success.

Oppressive Condition – Caustic Pollution: Characters must succeed on a DC 15 Constitution saving throw or suffer 1d3 acid damage.

HILLS, AVERNIAN: Either low mounds that undulate out of the wastelands or jagged promontories of razor-like rock that jut toward the blood red sky. The native life of Avernus, such as it is, often clings and clusters in the hills.

Oppressive Condition – Scree: See the Wastelands terrain below.

MOUNTAINS, AVERNIAN: There are generally two types of mountains in Avernus. Newer mountains that thrust up like broken blades of obsidian; raw and dangerous. And the older mountains that have been worn down by countless aeons, their gray immensity aching with an age incalculable to the mortal soul.

Oppressive Condition – Tremor: Avernus in general is tectonically unstable and this effect is magnified along the mountain crests. This condition indicates a tremor significant enough to disrupt travel, imposing a x ¾ speed modifier for the current watch.  1 in 10 such tremors are more serious, triggering significant hazards like an avalanche, rockslide, cave collapse, or the like.

This does not persist as an oppressive condition.

PLAINS OF FIRE: An iridescent, tarry putrescence seeps up through the soil here. These alchemical slicks catch on fire, a combination of small ever-burning wells and huge infernos miles long and high.

Failing a navigation check in the plains of fire, at the DM’s discretion, may indicate that the group has gotten cut off by a rapidly spreading fire, trapping the PCs in the eye of a firestorm.

It is never considered a clear day in the Plains of Fire.

Oppressive Condition – Extreme Heat: As described above.

PIT OF SHUMMRATH: A grand canyon more than a mile deep and filled with a lake of green slime that undulates as though breathing. The slime is actually the protoplasmic residue of an ancient devil imprisoned here by Archduke Bel many centuries ago, still possessed of some residual sentience and a telepathic ability to communicate (see p. 100 of Descent Into Avernus).

Large sections of the Shummrathian slime actually have a very thick skin, allowing the brave and foolhardy to walk across its slightly undulating surface. In slightly less gelatinous sections of the Pit, barges can dredge their way across.

Oppressive Condition – Telepathic Agony: An overwhelming telepathic burst emanates from the canyon, communicating in a single searing thought the eternal agony of Shummrath’s shattered consciousness. Characters must succeed on a DC 15 Wisdom saving throw or suffer 2d6 psychic damage.

WASTELANDS: The wastelands of Avernus look like sand, but are mostly made up of hard, sharp rocks akin to the quartzes and obsidian of the Material Plane. Footing can be treacherous.

Oppressive Condition – Scree: Traveling characters must make a DC 12 Dexterity saving throw each watch or suffer 1d3 damage. A character failing the saving throw must immediately attempt another, repeating until they succeed on a check or choose to stop traveling (in which case their distance traveled for the watch is halved).

WASTELANDS, CRACKED: The surface of Avernus is a rotten rind stretched across a festering fruit. In places, the ground has split apart. In cracked regions of the wastelands, the land is riven with fissures and ravines. Navigating these regions is difficult, either requiring great effort to circle around impassable chasms, or maze-like passages through the fissures themselves.

Oppressive Condition – Scree: See the Wastelands terrain above.

VOLCANIC PLAINS: Vast, smooth plains of black, basaltic rock. Sometimes shattered by tectonic upheavals. Often studded with fissure vents and bubbling pools of fresh lava.

An unusual feature of Avernian volcanic plains are the kipukas: Isolated areas of older lava flows surrounded by newer flows. On Avernus, these kipukas are often etched with the characters of some ancient and utterly forgotten tongue.

Oppressive Condition – Volcanic Event: Journeying near an active volcano is, of course, not safe in any circumstances, and even less so given the churning activity of a typical Avernian caldera. There are several volcanic events that could arise as an oppressive condition.

• A choking miasma of volcanic gas (see Oppressive Environment, above). More serious outbreaks of volcanic gas are also possible; resolve as a cloudkill
• An active lava flow, blocking the desired path of travel.
• A tephra fall, in which multiple inches and even several feet of ash can fall as precipitation. Add +2 to the DC of navigation checks and +4 to the DC of forage checks.
• A lahar, a violent mudflow formed from a slurry of pyroclastic material. (Resolve like an avalanche.)
• An eruption. This might be modeled by requiring the PCs to flee the hex within a certain timeframe.

Note: Although values are given for Highway speed, there are no such causeways in this section of Avernus. (They’re quite rare in Avernus in general.)

THE STYX

The effects of the River Styx are described on p. 76 of Descent Into Avernus.

It should be noted that these effects apply only to the waters of the river itself. The Styx is fed by a number of tributaries which do not share these effects until they join the main channel of the Styx. In Avernus, these tributaries may be water, but are more likely to be fouler effluvia. (In places within Avernus there are whole systems of rivers and lakes filled with nothing but the blood and bile and other fluids of mortal creatures spilling down into the Styx.)

NAVIGATING AVERNUS

Avernus… Its blasted, rock-strewn fields gape like festering wounds under a crimson sky. Neither stars nor sun brighten the infinite reach of this layer’s sky, for the blood-red light emanates from the air itself. There’s no way to keep time in Avernus, save by the screaming of the [suffering]. – Planes of Law (1995)

COMPASS DIRECTIONS: Cardinal and ordinal directions don’t exist in Avernus. (There is no rising sun, no stars in a night sky, and no magnetic field for aligning compasses.) This imposes disadvantage to navigation checks until a navigator has adapted to the oddities of Avernian geography (by successfully reaching an intended destination for the first time).

PLANAR COMPASS: A planar compass is a technomantic device which allows for navigation in the Outer Planes. A planar compass aligns to the nearest planar borders. In this particular region of Avernus that corresponds to the planar borders with Dis (to the “north” side of our map) and the Abyss (to the “east”). Thus Dis-ward, Abyss-ward, contra-Dis, and contra-Abyss.

Design Note: For simplicity, you might still want to use the familiar cardinal directions at the table. Here’s one way you could justify that: The word “north” actually derives from a word meaning “left” because it was the direction to the left of the rising sun. You could hypothesize an Avernian dialect in which the direction towards the Abyss (and the front lines of the Blood War) is adversa, and “Avernian north” is the direction to the left of that. In translation to the Common tongue, the common names – north, east, south, west – are extrapolated accordingly.

SIGHTING MOUNTAINS: In the absence of stars, sun, or magnetic fields, navigation in Avernus relies heavily on landmarks. In this particular region of Avernus, this is greatly aided by the Dispatrian Mountains that lie Dis-ward and the Praefervian Mountains to the contra-Dis.

On a clear day, both mountain ranges can be seen at a distance of two hexes (80 miles), but will frequently only be visible from 1 hex away. The thick haze of the Avernian atmosphere, however, usually reduces this to a single hex. Volcanic peaks indicated on the map (like Bel’s Forge in Hex H2) can similarly be seen at a distance of 1-2 hexes.

IDENTIFYING MAP LOCATIONS: If the PCs make inquiries, assume that Avernian natives can identify 1d6-1 locations on the player’s map.

OTHER AVERNIAN GUIDELINES

FORAGING: Food and water – particularly that suitable for mortal consumption – is hard to come by in Avernus. The native flora and fauna have a bitter or ashen flavor, and even drinkable water usually tastes foul.

Mortals make forage checks in Avernus at disadvantage. (Hell is not a place for mortals.) This does not apply to characters with demonic or devilish heritage (such as tieflings), who will find a broader range of Avernian wildlife suitable for their palates.

SPOTTING DISTANCE: Avernus is flat, which means there’s no horizon to block vision. With a clear line of sight you could hypothetically see an infinite distance… if it wasn’t for the atmosphere. On a perfectly clear day on Earth you can see about 150 miles through the atmosphere, but such conditions are rare on Earth and virtually impossible in Avernus.

Assume a 1 in 6 chance of a clear day.

On a typical day:

• A character taking the Sighting watch action can see their current hex.
• Mountains can be seen 1 hex away.

On a clear day (by Avernian standards):

• A character taking the Sighting watch action can see 1 hex (40 miles) away.
• Mountains can be seen 2 hexes away.
• Encounter spot distances in plains- or desert-type terrain (ashlands, wastelands, volcanic plains) are doubled. (Emphasize the disorienting nature of seeing creatures at such great distances to those unaccustomed to planar travel.)

UNSUITABLE TERRAIN: Land vehicles perform poorly in unsuitable terrain. Infernal war machines are well-suited to the Avernian wastelands, however, and are likely to only find mountainous terrain unsuitable. At the DM’s discretion they might also find unusual terrain like the Pit of Shummrath or the caustic bogs similarly problematic.

Some map icons from Hells Upper Levels by Keith Curtis via Inkwell Ideas.

Additional icons by Kevin Chenevert of RedKobold.com.

Go to Part 7C: Avernian Hex Key

Go to Part 1

In general, an expedition can navigate through the wilderness by landmark or they can navigate by compass direction.

NAVIGATING BY LANDMARK

Generally speaking, it’s trivial to follow a road, river, or other natural feature of the terrain. It’s similarly easy to head towards any visible landmark. The landmark or terrain feature will determine the route of travel and there’s no chance of becoming lost, so you can simply track the number of miles traveled.

IDENTIFYING LANDMARKS: If the PCs are unsure of a landmark but have had previous experience with it, it may be possible to identify it with a Wisdom (Survival) check, at the DM’s discretion. The accuracy and detail of the identification will depend on prior experience.

Example: A ranger is passing through the woods when they encounter a river. If it’s a river they’ve walked up and down before, the Wisdom (Survival) check might let them confirm that it is, in fact, the Mirthwindle. If they’re less familiar with the region, the check might tell them that this is probably the same river they crossed earlier in the day – it must be taking a southerly bend. If this is the first time they’ve ever seen this river in an area they’re not familiar with, the Wisdom (Survival) check won’t tell them much more than “this is a river.”

NAVIGATING BY COMPASS DIRECTION

Characters trying to move in a specific direction through the wilderness must make a navigation check using their Wisdom (Survival) skill once per watch to avoid becoming lost. The DC of the check is primarily determined by the terrain type the expedition is moving through, although other factors may also apply.

BECOMING LOST: Characters who fail the navigation check become lost and may veer away from their intended direction of travel, as indicated by a 1d10 roll on the diagram below. When lost characters exit a hex, they will exit through the face of the hex indicated by the die roll.

Characters who are lost remain lost. In the new hex neither their intended direction of travel nor their veer will change.

If characters who are already lost fail another navigation check, their veer can increase but not decrease. (If they have not yet begun to veer – i.e., they rolled a 5 or 6 on their initial veer check – then their veer can increase in either direction.)

Example: A lost party is already veering to the left when they fail another navigation check. A roll of 1-4 on 1d10 would cause them to exit the next hex two hex faces to the left of their intended direction, but any other result would not change their veer at all.

ALTERNATE VEERS: These alternate methods of determining veer may be useful, particularly if you are adapting these rules to be used without a hex map.

Absolute Degree: Roll (1d10 – 1d10) x 10 to determine the number of degrees off-course.

Compass Direction: Roll 1d10 and consult the diagram below. (The blue arrow indicates the intended direction of travel.)

USING A COMPASS: Compasses grant advantage to navigation checks. In addition, they automatically eliminate veer at hex borders even if the user doesn’t recognize that they were lost. (Even if you don’t recognize that you ended up off course, the compass constantly reorients you towards your intended direction of travel.)

LOST CHARACTERS

Once a character becomes lost, there are several factors to consider.

RECOGNIZING YOU’RE LOST: Lost navigators continue making a navigation check once per watch. If the check succeeds, they will recognize that they are no longer certain of their direction of travel.

Navigators who encounter a clear landmark or unexpectedly enter a distinctly new type of terrain can make an additional navigation check to realize that they’ve become lost.

Note: Some circumstances may make it obvious to the characters that they have become lost without requiring any check.

REORIENTING: A navigator who realizes that they’ve become lost has several options for reorienting themselves.

Backtracking: A lost character can follow their own tracks (see the Tracking watch action). While tracking allows them to retrace their steps, they must still recognize the point at which they went off-track. If a character is successfully backtracking, they may make a navigation check (using the Navigation DC of the terrain) each watch. If the check is successful, they’ll correctly recognize whether they were previously on-track or off-track. If the check is a failure, they reach the wrong conclusion.

Compass Direction: It requires a DC 10 Wisdom (Survival) check to determine true north without a compass or similar device. On a failed check, randomly determine the direction the navigator thinks is true north.

Setting a New Course: A lost navigator can attempt to precisely determine the direction they should be traveling in order to reach a known objective by making a navigation check at the Navigation DC of the terrain + 10. If the navigator fails the check, they immediately become lost. Determine their direction of travel like any other lost character.

CONFLICTING DIRECTIONS: If several characters in a single party all attempt to determine the correct direction of travel, make their Wisdom (Survival) checks separately. Tell the players whose characters succeeded the correct direction in which to travel, and tell the other characters a random direction they think is right.

Alternative Rule – Group Check: Alternatively, you can use the rules for group checks. If at least half the group succeeds on their Wisdom (Survival) checks, they have determined the correct direction of travel. If not, they immediately become lost.

FINDING LOCATIONS

The difficulty and complexity of finding a specific location within the wilderness varies depending on the character’s familiarity and approach.

Visible Locations: As described in Part 5: Encounters, some locations are visible from a great distance. Characters within the same hex as the visible location (or within a certain number of hexes, as indicated by the key) automatically spot a visible location.

On Road: If a location is on a road, river, or trail, then a character following the road, river, or trail will automatically find the location. (Assuming it isn’t hidden, of course.)

Familiar Locations: Familiar locations are those which a navigator has visited multiple times. Navigators within the same hex as a familiar location can be assumed to automatically find the location. (Within the abstraction of the hexmapping system, they’ve demonstrated sufficiently accurate navigation.) Under certain circumstances, navigators may also be considered “familiar” with a location even if they’ve never been there. (Possibilities include possessing highly accurate topographic maps, receiving divine visions, or using certain types of divinatory magic.)

Note: If navigators are flailing about in their efforts to find a familiar location – by repeatedly “missing the hex,” for example – the GM can decide to treat the location as being unfamiliar until they find some way to reorient themselves.

Unfamiliar Locations: Unfamiliar locations (even those a navigator has been to previously) are found using encounter checks.

In other words, when the navigator has gotten the expedition into the correct hex and a location encounter is generated, that indicates that the navigator has found the location they were looking for. Expeditions can also spend time to specifically search an area in order to increase the odds of finding a location. See Part 7: Hex Exploration.

Go to Part 5: Encounters