Basic GMing Tasks

**PTU Quick Navigation**

No matter what kind of campaign you’re running, there are some tasks that are universal to GMing. Adjudicating challenges, overseeing character creation, handing out Experience Points, all that good stuff. What about creating combat encounters? you might ask. That will get its own section in this chapter, don’t you worry. For now, let’s start from the top.

### **Character Creation And You**

The very first thing you need to present to your players after describing the premise and assumptions of your campaign is a set of guidelines for building their characters.

For a great many campaigns, what we outlined in the Character Creation chapter is appropriate: Level 1 Trainers with a single Level 5 or 10 Pokémon and $5000 to spend on items or to keep as cash.

However, you might decide that your PCs need to be more experienced from the start. Perhaps they’re seasoned Trainers brought together in a special task force by the Pokémon League, or maybe they’re just mildly experienced Gym Trainers out to find their own adventure.

Either way, you would simply raise the starting Level for characters in the campaign and allow them to choose more and higher leveled Pokémon to start. You may also decide to increment their starting money, increasing it anywhere from $500 to $750 per additional starting Level. Depending on what level your PCs start at, you may wish to limit what items they can purchase with their starting cash. For instance, you don’t want Level 1 Trainers buying Hyper Beam TMs.

It’s recommended that you don’t have your players start with more than perhaps three starter Pokémon at the maximum (and that’s for an experienced Trainer for a game that begins above Trainer Level 1) unless you’re having someone join in an ongoing campaign midway where the rest of the players already have established teams. A lot of the fun of Pokémon is discovering Pokémon and forming your team over time, and starting with too many Pokémon can undercut this experience.

If players worry about getting all the Pokémon they want, you may ask them to create a wishlist. Don’t follow it religiously, but it can help you satisfy your players.

### **Starter Pokémon**

In general, you may want players to select Pokémon with three evolutionary stages for their starters so their first Pokémon has room to grow with their Trainer over time. This isn’t a hard and fast rule, and you may allow two stage evolutions or even weak single stage Pokémon.

Using the classification of Underdog Pokémon is another way of making starter selection easier. But even within this category, you’ll want to keep some guidelines in mind. You may choose to limit “Pseudo-Legendary” Pokémon such as Dratini, Bagon, Gible, and Larvitar. When players begin with such rare Pokémon, it makes it difficult to give them somewhere more exciting to go.

On a more practical and mechanical level, some Pokémon that are available in the end-game of the video games tend to learn much more powerful Moves at lower levels than Pokémon available earlier on do. For instance, Larvitar learns Rock Slide at Level 19, which is a rather low Level for such a strong Move.

You should be careful when looking at the Ability choices Pokémon have as well. Abilities which give a boost to Damage Bases are very potent in the beginning stages of the game. Technician and Iron Fist are two examples of Abilities that can give Pokémon a huge early game boost. We aren’t suggesting you ban these Abilities outright, but you should watch carefully as your players select starters to ensure no one is going to be marginalized.

Generally, it’s a good idea to allow players to select the Ability, Gender, and Nature of their starter to avoid the RNG leaving them with a poor Pokémon for what’s supposed to be one of their most important companions.

Finally, it’s not a bad idea to give starter Pokémon an Inheritance List. For Pokémon without Egg Moves, you may even pick from Tutor or TM Moves for this list instead. Generally, the further you get into a campaign, the more interesting and unique Pokémon you’ll hand out to your players, whether it be shiny Pokémon, wellbred specimens, or simply rare catches. It can be easy for starters to be left behind mechanically, but a set of 2-3 Inheritance Moves can help offset this.

#### **Sample Starter Pokémon List**

Following the guidelines laid out on the previous page, here are a
number of Pokémon that make for good starters, sorted by the canonical Regional starters and then by Type. The
Types chosen for this are largely those which are less “mundane” and more likely to have fantastical elemental or
supernatural powers. Many Normal, Bug, and Flying Types are not only very common but less interesting than a
Fire or Electric Type.

Keep in mind that even within this list some Pokémon may be
slightly more useful than others in early levels, particularly because some Pokémon that make for great starters are
reliant on Struggle Attacks for the first few levels. Rock, Steel, and Ghost Type starter Pokémon may also end up
very powerful if most enemies have mainly Normal Type attacks early on, so GMs should be **very** careful about allowing these Types for starters, even if they are listed below. If early opponents are likely to have varied
Typed attacks, then this is much less of an issue.

 Charmander
 Squirtle

This isn’t meant to be a comprehensive list by any means! Your
players will likely have ideas for starters outside of this list, even within the Types represented, and that’s
perfectly okay. Just consider them on a case by case basis using the guidelines we’ve laid out already. There is also some repetition in this list. For the most part, we
try to populate it with three-stage Pokémon, but it isn’t always possible to find multiple three-stage families in a
given Type that are appropriate as Starters.

### **Rewards and Experience**

Another important part of GMing is handing out Experience so your PCs can grow and advance as they explore the world.

#### **Calculating Pokémon Experience**

Calculating Experience after an encounter is easy.

»» First off, **total the Level of the enemy combatants which were defeated**. For encounters where Trainers were directly involved in the combat, treat their Level as doubled for the sake of this calculation. For example, if your players fought a Level 10 Trainer with a level 20 Pokémon, Base Experience Value for this encounter is 40.

»» Second, **consider the significance of the encounter.** This will decide a value to multiply the Base Experience Value. See below for details on picking a significance multiplier.

»» Third, **divide the Experience by the number of players gaining Experience**. Divide by the number of Players – not the number of Pokémon. If a Trainer used multiple Pokémon, he will have to split his experience among the Pokémon he used. The resulting number is how much experience is gained by each Trainer!

#### **Significance Multiplier**

The Significance Multiplier should range from x1 to about x5, and there’s many things to consider when picking this value.

First, consider narrative significance. This will inform your “base” significance multiplier.

An encounter against wild Pidgeys probably doesn’t have any significance; an encounter against a rival trainer has more; and an encounter for the championship title has lots!

»» Insignificant encounters
should trend towards the bottom of the spectrum at x1 to x1.5.

»» “Average” everyday
encounters should be about x2 or x3.

»» More significant
encounters may range anywhere from x4 to x5 depending on their significance; a match against an average gym leader might merit as high as x4. A decisive battle against a Rival or in the top tiers of a tournament might be worth x5 or even higher!

Next, consider the challenge and threat being posed. Even if a wild Pokémon doesn’t have much narrative significance, a very strong wild Pokémon may be able to inflict serious damage to trainers and their Pokémon. Conversely, a fight against an unskilled Gym Leader might hardly be a challenge at all. Lower or raise the significance a little, by x0.5 to x1.5, based on the difficulty of the challenge. Of course, don’t use this to punish particular party members if they have an advantage due to type or similar – this should be used to consider more sweeping advantages based on numbers or Level differences.

#### **Regulating Experience**

As written, Experience can only be distributed to Pokémon who participated directly in an encounter, and it can be split however the player sees fit, even if that means putting all of the Experience for a large encounter into a single Pokémon. Note that unlike in the video games, Fainted Pokémon can still gain Experience.

In some cases, however, such as boss encounters that mark the end of a major plot arc or chapter in your campaign, you could choose to allow a portion of the Experience being handed out to be distributed even to Pokémon that didn’t participate in battle.

This is especially useful if you’ll be using timeskips in your campaign. It’s also a handy tool to allow players to catch up weaker Pokémon without wasting session time looking for Pidgeys to “grind” on.

On the other hand, you may want to regulate how much Experience can be put into any single Pokémon after an encounter, even if it was a Pokémon that was used in that battle. (Letting one Pokémon on a PC’s team greatly outstrip the average Pokémon Level in a party is a bad idea!) You could institute a rule that Pokémon above a certain Level can only receive up to a certain cap of Experience from the encounter, for instance or simply put a flat cap on how much Experience any one Pokémon can receive. This can result in a player having too much Experience to allocate properly if they only used one or two Pokémon in a battle, so you should combine this with the above guideline for allowing nonparticipant Pokémon to gain Experience as well when used in very large encounters.

#### **Trainer Levels and Milestones**

In Pokémon Tabletop United, there are two ways for Trainers to gain levels; **Milestones** and
**Experience**.

**Milestones** are the most straight forward way of leveling up. A Milestone represents meeting a significant goal. For example, gaining a Badge or a Ribbon in a contest should be causes for a Milestone Level-Up. Other events such as defeating a major opponent or very challenging “boss”, or fulfilling a long-term goal that impacts the narrative, should also grant Milestone Level-Ups, subject to GM discretion.

Here’s a sample list of other Milestones you can use for campaigns without a Pokémon League or characters who have no interest in the League.

**High Seas Pirate Campaign**: +1 Level for each island fully explored or enemy flagship raided and looted.

**Space Opera Campaign**: +1 Level for each planet explored and catalogued for the fleet.

**Pokémon World War Campaign**: +1 Level for each enemy city conquered or major encampment destroyed.

**Noir Detective Campaign**: +1 Level for each mob boss taken down or arrested.

The other way to Level Up is from gaining **Experience**. Whenever a Trainer reaches 10 Experience or higher, they immediately subtract 10 Experience from their E**xperience Bank** and gain 1 Level. Leveling Up through a Milestone does not affect your Experience Bank.

There is only one automatic source of experience: Pokémon. Whenever a Trainer catches, hatches, or evolves a Pokémon species they did not previously own, they gain +1 Experience.

**Note**: Not all characters will want to catch a lot of Pokémon, so it may be a good idea to create alternate Experience goal posts for other characters. You would likely keep Experience from capturing Pokémon for the Capture Specialist since they will do this activity frequently and need to be rewarded for it. However, for another character, they gain no Experience from captures, but you might say they gain 3 Experience every time they compete in a tournament, on top of the Experience the group would normally gain from those sessions. Scale these rewards to how often you think they will occur in comparison to capturing Pokémon. You may even decide to do this replacement with Milestones as well to create custom advancement goal posts for everyone. The League battler certainly might benefit from Gym Badges as Milestones, but you may decide a detective instead arrests criminal Team admins and officers as their Milestones.

All other Experience must be granted by the GM, and it is up to the GM to decide when to grant experience, and how much, and thus decide the pace of leveling for the campaign.

#### **Calculating Trainer Experience**

Like with Pokémon Experience, GMs will have to decide how much Trainer Experience to grant after each encounter; and again, we encourage GMs to consider narrative significance and challenge as the main determining factors.

A scuffle with weak or average wild Pokémon shouldn’t be worth any Trainer experience most of the time. An average encounter with other Trainers or with stronger wild Pokémon usually merits 1 or 2 Experience at most.

Significant battles that do not quite merit a Milestone award by themselves should award 3, 4, or even 5 Experience. Alternatively, “lost” battles that would have otherwise awarded a Milestone Level-Up may be worth 1 or 2 Experience as well, or even more if it is a significant and non-repeatable event.

Experience for Trainers can and should also come from non-combat goals and achievements as well, both as a party as an individuals.

As a party, non-combat goals could include narrative progress, such as reaching a new Town or Route, or unraveling a bit of political intrigue. If nothing else, if you have session that has little in the way of action or intrigue, it wouldn’t be a bad idea to grant your party +1 Experience for the session anyway.

As individuals, you probably should not give out too much experience too often unless you’re using the alternate Experience goal posts method, but don’t be shy about giving it for particular achievements. For example, the Ace Trainer that finally got its unruly Camerupt to follow orders deserves a little Experience.

#### **Money Matters**

Giving your Trainers money can sometimes be a bit tricky. In the ideal situation, you want to keep most of your PCs poor enough that they need to constantly be on the lookout for sources of income; but you also want them to have enough money to purchase basic needs, and indulge occasional splurges. Here are some helpful ideas or guidelines that may be of use.

**Wagers**: Other trainers that travel the region may occasionally challenge your PCs to battles. Usually, they’ll make a wager, agreed on by both parties. Whoever wins gets both sides of the wager. Simple. Young, inexperienced trainers often don’t have much cash to wager; maybe 2000 at a high bid, but usually much lower. Older, richer, and more experienced trainers may wager up to 5000 however.

**Contests & Gym Battles**: If your Campaign involves Pokémon Gyms, let Gyms grant money without the risk of a wager. A reward of 4,000 to 8,000 or even more is probably in order – and of course, a TM as well! Contests may give similar rewards, perhaps giving a Held Item instead of a TM.

**Parents**: Parents or other family members may wish to help a little bit financially! They may send money, coupons, or vouchers electronically.

**Promotions & Raffles**: Like real-life stores, PokéMarts and PokéCenters may sometimes run promotional offers. Punch Cards for every 100 spent that grant 500 in credit for 10 punches might be a nice way to help trainers keep up on Potions and other basic necessities.

Occasional Raffles for free items may also be nice; on every purchase over 2000 for example, let them make a 1d20 roll; upon success, they win a nice Poké Ball or Restorative item of your choice.

**Side Jobs**: In the grand tradition of RPGs, side quests are always a good source of income! The amount awarded should be consistent with the difficulty or danger of the task. Some players may also wish to sell goods or services, such as items they can craft or the use of Features from Mentor and similar Classes.

**The Ground**: The floor can be a great ally to your PCs! If you feel your trainers are having trouble keeping their inventories stocked, once per route, let them make a 1d20 Luck Roll, and grant them items based on the result. Here’s a chart that may help – feel free to change the chart as little or as much as you wish.

**1-4** Nope.avi You find nothing

**5 - 6** Battle Enhancers A Random X-Item

**7 – 8** Money You find 1d4 x100 bucks!

**9-10** Berries Any Random Berry

**11-12** Poké Ball Any Random Poké Ball

**13-16** Status/Healing Any Restorative

**17** Evolutionary Stones Any Random Evolutionary Stone

**18** Performance Enhancers Any Random Vitamin

**19** Hold Item Any Random Hold Item

**20** TM Any Random TM

**Conversion Rate**: Wanna run your campaign on dollars instead of $? Easy! $1 = $50. This puts basic Poké Balls at $5 and candy bars at $1.50 Even if you want to run your game in $, this is a useful way to price random items.

### **Creating Shops**

Stumped on what kinds of shops to fill your world with? Here are 7 ideas for types of shops that will fit most Pokémon worlds and towns.

**Commonly** available products will show up in a store in most any town, save perhaps for very out of the way areas. Products that are “**Possibly**” available are less common and may be in stock only due to the surrounding environment, such as a Travel Shop near a cave stocking Dark Vision Goggles. “**Rarely**” available items are usually the providence of more specialized or especially large shops, such as the department stores found in cities like Goldenrod and Celadon. Feel free to mix and match products across rarity levels to best suit your setting and the shops in your world.

**PokéMarts**

**Commonly**: Basic Balls, one or two Specialty Poké Balls

**Possibly**: Great Balls, two or more Specialty Poké Balls, Held Items worth $2500 or less, one to three Evolutionary Stones or Keepsakes, one to three TMs

**Rarely**: Ultra Balls, several Specialty Poké Balls, Held Items worth $2500 or more, large selection of Evolutionary Stones and Keepsakes, large selection of TMs

**Pharmacy**

**Commonly**: Candy Bars, Potions, Antidotes, Awakenings, Burn Heals, Ice Heals, First Aid Kit, Chemistry Set, Repels

**Possibly**: Full Heal, Revive, X-Items

**Rarely**: Full Restore, Vitamins

**Very Rarely**: Pester Balls

**Travel Shop**

**Commonly**: All items listed in the “Travel Gear” section, Repels, Cooking Set, Dowsing Rod, Poké Ball Tool Box, Portable Grower, Snow Boots, Running Shoes, Flippers, Jungle Boots, Old Rods, Hand Nets

**Possibly**: Light Armor, Stealth Clothes, Dark Vision Goggles, Gas Masks, Helmets, Re-Breathers, Good Rods, Glue Cannons, Weighted Nets, Light Shield

**Rarely**: Heavy Armor, Heavy Shield, Super Rods, Wonder Launcher, Caltrops, Smoke Balls

**Market**:

**Commonly**: Candy Bars, Enriched Water, Tier 1 Berries, Baby Food, Poffin Mixer

**Possibly**: Super Soda Pop, Leftovers, Tier 2 Berries, Apricorns

**Rarely**: Sparkling Lemonade, MooMoo Milk

**Herb Shop**

**Commonly**: Energy Powder, Heal Powder, Poultices, Tier 1 Berries, Honey

**Possibly**: Energy Root, Revival Herb, Tier 2 or 3 Berries

**Fashion Shop**

**Commonly**: Fancy Clothes, Sunglasses, Running Shoes, Contest Accessories, Contest Fashion, Groomer’s Kit, Egg Warmers, Poffin Mixer

**Occult Shops**

**Commonly**: Useless hogwash with no effect

**Possibly**: Cleanse Tags, Dream Mist

**Very Rarely**: Magic Flutes

### **Tutors and Other Services**

Occasionally, your players may want access to a service provided by Class Features – a Move Tutor, for example,or perhaps a breeder. The availability for these services depends on you, and you should consider your setting before making any service available.

That said, below are some of the more common NPC services accompanied by recommended frequencies of availability and prices.

**Commonly** available services probably can be given out pretty freely without hurting anything. “**Possibly**” an “**Rarely**” available services should be considered a bit more before inserting them into your setting. Also note, you should of course mix and match across rarity levels as it suits you; A breeder with Master Rank Pokémon Education could only have Rattatas and Pidgeys for adoption, for example.

**Specialist Tutors**: These Tutors have taken the “Tutoring” Feature, and can teach only a single specific Move to Pokémon that could learn that Move via Level-Up, TM, Egg-Move list, or Move Tutor. Having one of these per town can be an interesting way to keep players looking forward to new locations. Prices should vary from $1000 to $3000, depending on the strength of the Move in question.

**Generalist Tutors**: These Tutors have taken Mentor Features, and are rarer than Specialist Tutors and often more expensive, but can provide varied services.

**Commonly**: Latent Potential ($800)

**Possibly**: Move Tutor (Varies Per Move), Corrective Learning ($1200)

**Rarely**: Changing Viewpoints ($2500), Versatile Teachings ($2500)

**Chefs**: Rare gourmet foods are relatively common in big cities in restaurants, food stalls, and cafes. However, they are often sold at a significant mark-ups. Items such as Vitamins and Refreshments are usually sold at their normal market price.

**Commonly**: Super Bait ($400), Vile Bait ($400), Honey Candy ($150), Stat Suppressants ($500)

**Possibly**: Salty Surprise and Similar ($600), Preserves (Matches Price of original item)

**Rarely**: Dumplings (Combined Item Price + $500)

**Fashionistas**: Oh baby! Salons are common in big cities, and their services widely available - if pricy. Their makeovers will last until your next extended rest.

**Commonly**: Stylish Makeover ($1000)

**Rarely**: Elaborate Masquerade ($1000)

**Breeders**: These are very rare. The difference between various Breeders are their Skill Rank in Pokémon Education which affects which traits they can control when Breeding, and the Eggs or young Pokémon they offer for adoption. You may want to consider the presence and availability of Breeders in your game very carefully.

**Commonly**: Adept Pokémon Education, Common and cute Pokémon such as Rattata, Sentret, Pidgey, Lillipup, etc. ($1000)

**Possibly**: Expert Rank Education, Slightly Rarer Pokémon such as Pichu, Sandshrew, or Poliwag ($5000)

**Rarely**: Master Rank Education, “Starter” Pokémon or other rare breeds ($10,000 or more).

**Very Rarely**: Stronger or Rare Pokémon ($15,000 or more)

As a final note, some of these services such as Move Tutoring or Hatching Pokémon Eggs may also be good options
to offer as prizes for defeating a Gym Leader.

### **Setting Skill Check Difficulties**

Some basic ideas for setting difficulties for Skill Checks were
touched upon earlier in the book, but here’s a more thorough and mathematically rigorous treatment of the subject, if
that’s your thing.

First of all, here’s a mathematical breakdown of percentage chance
of success for a given DC a +0 modifer applied to the raw Skill Check. Trainers will often have Equipment, Edges
that give them bonus modifiers to their Skills, and other effects which will give them higher probabilities for
success than these baseline values might indicate. Be sure to account for that when setting DCs.

If you need to see the chances of success/failure for a specific
Trainer, then simply adjust the DC to account for the difference in their modifier. For every point above +0,
subtract 1 from the DC. For example, a Trainer making a DC 14 Athletics check with a +4 modifier to theirAthletics from
equipment and other effects would have the chances associated with DC 10 on the chart. So 84.1% at Adept, 50%
at Novice, and 16.67% at Untrained.

**DC 4** - 90%+ success rate at Untrained or higher, 50% success rate at
Pathetic

**DC 6** - 90%+ success rate at Novice or higher, 72.22% at Untrained,
16.67% success rate at Pathetic

**DC 8** - 83.8% success rate at Novice, 41.67% at Untrained, impossible at
Pathetic

**DC 10** - 84.1% success rate at Adept, 50% at Novice, 16.67% at Untrained

**DC 12** - 90%+ success rate at Expert or higher, 76.08% at Adept, 37.5% at
Novice, 2.78% at Untrained

**DC 14** - 84.8% success rate at Expert, 55.63% at Adept, 16.2% at Novice,
impossible at Untrained

**DC 16** - 90%+ success rate at Master, 69.48% at Expert, 33.56% at Adept,
4.63% at Novice

**DC 18** - 79.42% at Master, 50% at Expert, 15.9% at Adept, less than 1% at
Novice

**DC 20** - 63.69% at Master, 30.52% at Expert, 5.4% at Adept, impossible at
Novice

**DC 22** - 45.43% at Master, 15.2% at Expert, 1.16% at Adept

**DC 24** - 27.94% at Master, 5.88% at Expert, less than 1% at Adept

**DC 26** - 14.46% at Master, 3.24% at Expert, impossible at Adept

**DC 28** - 6.08% at Master, less than 1% at Expert

**DC 30** - 1.97% at Master

That said, here’s an easy breakdown – the following DCs represent the average roll for a Skill Check at these DCs.

Use them when you want the PCs to succeed most of the time but still want a chance for failure. You should also frequently increase them by a couple points for more difficult situations, especially because most characters will have bonus modifers to their specialty Skills.

**Untrained check** – DC 7

**Novice check** – DC 10

**Adept check** – DC 13

**Expert check** – DC 17

**Master check** – DC 21

Armed with these percentages, or simply the easy breakdown if you wish, you can decide how difficult to make the Skill Checks in your campaign! First of all, what kind of tone are you going for in your campaign? If you’re emulating the Pokémon anime, then DCs may tend toward the easy side. Leaps of faith from building tops to passing airships and hot-air balloons may be difficult but doable even for relatively inexperienced (Novice) acrobats, say, a DC of 12 or 14. Essentially, “anime physics” are in play, and Trainers can expect for acts of heroism to have moderately high chances of success.

Now, if you were running a gritty noir campaign, or a downtrodden post-apocalyptic campaign, you may decide the overall tone is grimmer, making Skill Checks more difficult. That same jump could easily be a DC 20 Acrobatics Check, representing the difficulty of accurately leaping from a building to a quickly moving airship. With more realistic physics in play, Trainers will have to be careful what risks they take.

Second, think about what each level of Skill Rank represents in your campaign. For example, generally, Adept Rank is enough for someone to make a living by their Skill.

So when considering whether or not one of your PCs with an Adept Education: Technology Skill can successfully repair a car engine in a shop, think about whether or not the problem is one they’d be able to routinely handle at any given car mechanic you’d visit. Simply replacing a part? At DC 10, even someone without bonuses from equipment and other modifiers would succeed an overwhelming amount of the time with an Adept Skill. If it’s a more esoteric problem involving a rarer model of car? At DC 17, even someone with a +3 total modifier from Categoric Inclination and Skill Enhancement and an Adept Skill in Technology is only going to be able to solve the problem a little over half the time – and that might be accurate.

It could be the kind of problem that gets the chief mechanic called in at the shop or requires further research and special equipment that might give a bonus to the Skill Check on a later reattempt.

We don’t really believe in handing out tables of set DCs for particular tasks, but hopefully, having these numbers on hand and this guide will allow you to properly set DCs for Skill Checks in a variety of campaign types!

#### **Circumstantial Difficulties**

When deciding the difficulty for a Skill Check, the target number depends on the difficulty of the task itself, but Skill Checks aren’t done in a vacuum. The environment and other external circumstances will affect the difficulty of a task. However, trying to map different activities to a scale of DCs that range from the single digits up to 30+ is a daunting task, and it can be hard to conceptualize that wide a range. It can seem like once players rank up their skills to a certain point, they can’t fail at anything anymore.

The recommended solution here is to apply penalty dice to checks in severe circumstances. For each mitigating circumstance that makes a task more difficult, roll 1d6 and subtract that amount from the character’s Skill Check. For example, you might set the difficulty for a Perception Check to spy a hidden scroll in the nook of a tree at 12. A character with Adept Perception and a +2 bonus from Skill Enhancement would easily make this check most of the time as they’d average a roll of 16.

However, if they’re making this check while in the dark and during a violent rainstorm with high speed winds blowing, you may decide to roll two penalty dice against their check in addition to the DC you set for the task. This makes it easier to create difficult tasks for highly skilled characters without needing to conceptualize an enormous range of DCs.

The reason penalty dice are rolled instead of merely subtracting d6s from the player’s roll is that we wanted to avoid situations where a player literally could not roll a check because all of their dice have been subtracted due to circumstantial modifiers. While it is exceedingly unlikely that a player might succeed in a roll where the penalty dice equal or exceed the dice they would roll for a check, it’s still possible, and they should have a chance to
attempt that roll.