How competent should NPCs be?

[Jay R]

Even 1st level characters stand head and shoulders above the rabble. Look at your typical human commoner - 2 HP and +0 to hit with one simple weapon. A level 1 fighter could cleave through half a dozen of these guys and then go back to his beer.

There is a huge difference between "head and shoulders above the rabble" and "the baddest-assed of the badass." If you are revising your statement to "the PCs stand head and shoulders above the rabble," then we are in agreement. If not then you aren't defending your actual position.

Having incompetent ''goofy'' foes or weak foes, just wastes time. If you have powerful PC that can lay waste to weak or goofy foes in less then a round, then your just wasting time even having that round.

I agree with what I think you meant, but not with what you said. Numbers matter as well as level. 100 weak, goofy kobolds can be a serious problem for a party.

I certainly agree that the sum total of the bad guys must be able to threaten the sum total of the party, but that can be done with enough incompetent foes all firing together.

You can't really have the PC's be ''too awesome'', otherwise the game becomes pointless.

Agreed completely.

[jedipotter]

I agree with what I think you meant, but not with what you said. Numbers matter as well as level. 100 weak, goofy kobolds can be a serious problem for a party.

D&D gets really tricky with the power levels, and that is even if your not optimizing, power gaming or anything else.

Weak, goofy kobolds can still be a threat....but they will need a power boost to do so.

[hamishspence]

Depends on the NPC.

Dirt Farmer? 5% as optimized as a PC.
Town Guard? 20-25%
Royal Guards? 30-35%
Badass captain of he Guard? 55-60%
Badass warrior, who is eiher friend or rival to one or more PCs? 75-90%
BBEG's first lieutenant? 85-95%
BBEG? >95%


EDIT: Note: this is a rough guideline.

Yup - a low-level BBEG could get away with being more optimized than the PCs. They might feel a bit cheated though when, say, at 8th level, the CR4 heavily optimized BBEG is a very tough fight, yet gives them minimal XP afterward.

[Storm_Of_Snow]

There should be NPCs who are more competent than the PCs. There should also be NPCs who are less competent than the PCs.

Agree there - but there should always be something even the most competent and thorough thinking NPC won't think of. An underling with something the PCs can exploit, despite their bosses best efforts to make sure that doesn't happen, an access method to their lair that they don't know about, an unlikely circumstance (say they've sent a group into the nearest town for supplies, but they got caught up in a bar fight and arrested), or someone just bulldozing through their front door, even though it's as well defended as they could make it.

However, the PCs won't be able to use it against them twice.

Or circumstances can conspire against them - even the best NPCs won't have infinite money or resources, or they might have planned for a defence but not had the time to put it in place when the PCs come calling.

Then, of course, there's the NPC's own psychology - take the Riddler in Batman. He doesn't just want to commit his crimes, he wants to beat Batman intellectually, and prove it to the world. Some people just can't help themselves.

Effectively, you need to build their defences and escape routes first, then let the PCs take a run at them. If circumstances would allow them to add something in depending on what the players do, then you can react to that, but otherwise, you can't just throw something in place because the players have thought of something you didn't and you don't think it's time for the bad guy to be brought down yet - that's why you've put their escape routes in place.

If they've blocked them all off, let them arrest the bad guy, congratulate them, and either spring him later on or let him carry on from inside his prison cell.

The town guard is not well optimized, but the royal bodyguard is.

Or in some cases, the town guard is incredibly competent, because they're out on the streets day after day, and the royal guard's a bunch of political appointees, lickspittles and first sons who've inherited the position from their fathers, who barely know the sharp end of a sword from their backsides and their main job in life is to wear an ornate uniform and look good at state occasions, while the real job of protecting the monarch and his family's done by someone else.

[Frozen_Feet]

NPCs should be as competent as their role in the setting requires. Scaling them against the PCs, specifically, only makes sense if PCs are the main competition or threat to the NPCs. In most cases, you should think larger: who are all the other people the NPC has to work with or against? What would they actually need to know and be able to accomplish to be in the position they are in?

Doing it this way, you'll find out that being optimized to theoretical optimums would rarely make sense. Think of it in the terms of evolution, non-random survival of random traits. The process doesn't aim for the "best", it aims for "least worst" or "good enough". To become a level 5 barbarian, you only need to survive the preceding levels, you don't need to be able to kill every foe with a single blow without taking any damage.

[Flickerdart]

Weak, goofy kobolds can still be a threat....but they will need a power boost to do so.

If you give weak kobolds a power boost, they are no longer weak.

[LibraryOgre]

Weak, goofy kobolds can still be a threat....but they will need a power boost to do so.

Not really; that was the entire point of Tucker's Kobolds, after all. Sure, they're "only kobolds", but if you have them take their money and such an invest it in traps and such, it can turn a speedbump into a serious threat... not because they have great individual power, but because they've leveraged time and location into a force multiplier.

[Mr.Moron]

Roughly as component as they need to be to provide the kind of engagement you intended for the players to experience.

[janusmaxwell]

Related question, possibly.

What would be the equivalent skill level for DnD ranks?

For example, playing WOD games and in those, having 1 dot in something means poor and 2 is average, with the maximum in the realm of human ability capping at 5.

What's the equivalent in skill ranks for ability in D20 skill rank system? would it be 10 considered average with 20 being the best possible without magic?

The reason I ask is that I don't want to have a noble who has spent the entirety of his life in and around the upper-crust of society and his ranks in Knowledge Nobility amounts to "average/below average".

[Flickerdart]

Related question, possibly.

What would be the equivalent skill level for DnD ranks?

For example, playing WOD games and in those, having 1 dot in something means poor and 2 is average, with the maximum in the realm of human ability capping at 5.

What's the equivalent in skill ranks for ability in D20 skill rank system? would it be 10 considered average with 20 being the best possible without magic?

The reason I ask is that I don't want to have a noble who has spent the entirety of his life in and around the upper-crust of society and his ranks in Knowledge Nobility amounts to "average/below average".

Skill ranks don't really affect anything, what you're after is the total modifier. In such a case, +0 represents your random guy off the street, average for a practitioner of the skill is about +5 (DC15 Knowledge checks are "basic questions," DC15 is required to craft martial weapons, a DC15 performance is "enjoyable"). +10 is considered good (DC20 to craft a masterwork or "superior" item, a "great performance" that gives you regional prominence, or answer a tough question). Most tables for checks that non-adventurers would perform generally cap out at around DC30, requiring a +20 modifier for hardcore expertise.

[Beta Centauri]

I despise skill ranks for NPCs - if I want my NPC to be able to do something, then it's able to do that thing - but one thing I always wondered about was how the "Profession" skill figured in. A blacksmith wouldn't need to have Craft: Weaponsmithing, Craft: Armorsmithing and whatever else in order to make a living as a blacksmith; they'd just need Profession: Blacksmith. Even a 1st level blacksmith, with minimal training, would make an average of about 10 gold a week, which seems pretty good.

What does that 10 gold represent? Seems like it could represent anything. That blacksmith could be churning out high-quality masterwork weapons and armor, with a razor thin profit margin. That would make that NPC far more competent at blacksmithing than a PC with a massive modifier in Craft: Weaponsmithing.

For that matter, I don't see why you couldn't have NPCs with Profession: Adventurer. They're quite as competent as the PCs and make a living, but it's nothing grand.

[Flickerdart]

For that matter, I don't see why you couldn't have NPCs with Profession: Adventurer. They're quite as competent as the PCs and make a living, but it's nothing grand.

The kind of pocket change you make with Profession would mean that these guys "quest" in shuttered stores and morgues - they're basically scavengers and looters.

[Beta Centauri]

The kind of pocket change you make with Profession would mean that these guys "quest" in shuttered stores and morgues - they're basically scavengers and looters.

Not at all. They're simply not as successful as the PCs. Adventuring in the real world is financially risky, even for the very competent, so it's plausible that most fictional adventurers wouldn't hit it big. Furthermore, the Profession roll just tells us how much they make. It could be that once costs for equipment, traveling, and healing are covered that they are making merely a comfortable living. Or maybe they're highly altruistic and adventure not for gold but for artifacts that they give to museums, which fund their expenses plus a modest stipend.

[jedipotter]

Not really; that was the entire point of Tucker's Kobolds, after all. Sure, they're "only kobolds", but if you have them take their money and such an invest it in traps and such, it can turn a speedbump into a serious threat... not because they have great individual power, but because they've leveraged time and location into a force multiplier.

Tuckers Kobolds was a couple of Editions ago. And it does not account for optimization.

Once the PC's are 10th level or so in Editions like 3.5E, anything mundane is a bit pointless. Burning oil? Oh, like 1d4 damage? Smoke: ok make a save vs DC 15 with your plus 15. And teleporting past/away from things.

Not to mention that the under 1 CR foes have no chance of hitting a 10th level character unless they roll a 20.

To do Tuckers Kobolds in 3.5E, you need to up the power level of the kobolds.

[Flickerdart]

Not at all. They're simply not as successful as the PCs. Adventuring in the real world is financially risky, even for the very competent, so it's plausible that most fictional adventurers wouldn't hit it big. Furthermore, the Profession roll just tells us how much they make. It could be that once costs for equipment, traveling, and healing are covered that they are making merely a comfortable living. Or maybe they're highly altruistic and adventure not for gold but for artifacts that they give to museums, which fund their expenses plus a modest stipend.

Yeah, but they're not actually good at fighting or anything (as evidenced by their lack of fighting skill) which makes these alternate explanations really hard to swallow. Kind of like a guy with ranks in Profession (Locksmith) but absolutely no Open Lock ranks is still bad at picking locks despite making money doing it.

[Beta Centauri]

Yeah, but they're not actually good at fighting or anything (as evidenced by their lack of fighting skill) which makes these alternate explanations really hard to swallow. Kind of like a guy with ranks in Profession (Locksmith) but absolutely no Open Lock ranks is still bad at picking locks despite making money doing it.

Profession says "You know how to use the tools of your trade, how to perform the profession’s daily tasks, how to supervise helpers, and how to handle common problems."

An NPC with Profession: Blacksmith knows how to use a forge, anvil, hammer, tongs, etc., can complete everyday tasks associated with blacksmithing (forging items, making repairs, toting coal, etc.), can supervise his apprentices and can deal with problems like tricky suppliers and customers, thieves, and injuries.

However, even though this blacksmith can forge items, and even items of masterwork quality and of special materials if that is an "everyday" task, this blacksmith can't succeed on a Craft: Weaponsmithing roll to save their life. But that doesn't mean they can't weaponsmith. They're a blacksmith. Of course they can weaponsmith. It's preposterous to claim otherwise.

An NPC with Profession: Adventurer knows how to use weapons, spells, thieves tools, rope, lanterns, etc., can complete everyday tasks associated with adventuring (exploring, traveling, fighting off monsters, etc.), can order henchmen around, and can deal with problems like injuries, getting lost, bad weather, etc.

However, even though this adventurer can fight monsters, and even tough monsters if that is an "everyday" task, this adventurer can't succeed on an actual attack roll to save their life. But that doesn't mean they can't fight. They're an adventurer. Of course they can fight. It's preposterous to claim otherwise.

The thing is that neither of these NPCs do any specific thing. Everything they do is in the abstract. It's never actually "on screen." If the PCs challenge the NPC adventurer directly, of course they'll lose. Then again, the NPC adventurer is not at risk of dying on an adventure the same way the PCs are, and can't expect to make the same money the PCs can. Similarly, the NPC blacksmith can't craft a specific sword for his personal use, but also never has to worry about failing to make a profit in a given week.

I'm not saying this, the game is. Zoom in, play everything out, get into specifics, and the PCs are going to vastly outclass the NPCs. Put things in the abstract though, as one usually will for NPCs, and they're perfectly competent and capable.

The bottom line of course, and why I hate skill ranks for NPCs, is that the rules are not sufficient to create or even usefully simulate the game world. If a GM wants a blacksmith, they don't have to stat the blacksmith out, they just say there's a blacksmith, who can or can't sell what the PCs want for a given price.

Kind of like a guy with ranks in Profession (Locksmith) but absolutely no Open Lock ranks is still bad at picking locks despite making money doing it.

I missed this before.

Yes, that's right! That guy picks locks in a professional context. PCs pick locks in a game context. The professional locksmith picks locks with a speed and success rate adequate to make 1d20/2 gold per week. He's not doing it in a dungeon or with monsters breathing down his neck, and if you pit him against a PC with ranks in Open Locks, and the PC simply wins. No point in even rolling, really. That doesn't mean the locksmith is incompetent.

[Jay R]

Weak, goofy kobolds can still be a threat....but they will need a power boost to do so.

Only if you expand the meaning of "power boost" to include being on top of the mountain ready to start an avalanche, or having the only boat that still floats, or knowing where the safe path through the Death Swamp is, or even just having a few hundred archers and being out of reach of the melee fighters.

[Susano-wo]

However, even though this blacksmith can forge items, and even items of masterwork quality and of special materials if that is an "everyday" task, this blacksmith can't succeed on a Craft: Weaponsmithing roll to save their life. But that doesn't mean they can't weaponsmith. They're a blacksmith. Of course they can weaponsmith. It's preposterous to claim otherwise.

Um, no. horseshoes and nails (and other basic blacksmithing tasks) require no where near the expertise it takes to craft anything other than crude weapons. normal quality weapons, much less masterwork ones require special training. maybe another skill might be more apropriate?

Profession is a way to abstract making money from a certain type of job. crafting is meant to be a concrete way to produce certain types of items. To examine it too closely shows the cracks in the system. (that you should be able to craft basic items with profession blacksmith, but by RAW you cannot) Though this can be mitigated by allowing profession trained characters to produce the basics as though crafting, but anything aside from that (like useful weapons or quality clothing, etc,) require craft training.

[Beta Centauri]

Um, no.

Ah, the classic sound of condescension. Hopefully you didn't mean it that way.

horseshoes and nails (and other basic blacksmithing tasks) require no where near the expertise it takes to craft anything other than crude weapons. normal quality weapons, much less masterwork ones require special training. maybe another skill might be more apropriate?

Oh, okay. Profession: Specially Trained Blacksmith.

Profession is a way to abstract making money from a certain type of job. crafting is meant to be a concrete way to produce certain types of items. To examine it too closely shows the cracks in the system. (that you should be able to craft basic items with profession blacksmith, but by RAW you cannot) Though this can be mitigated by allowing profession trained characters to produce the basics as though crafting, but anything aside from that (like useful weapons or quality clothing, etc,) require craft training.

Useful weapons, quality clothing, or anything else in a D&D game comes from somewhere. Normally where it comes from doesn't matter, but it's plausible to imagine such an NPC having ranks in a Profession skill. The Profession skill contains everything necessary to work in that profession. It doesn't address actual output or services rendered, but of course the NPC does have output or did perform a service. So would a PC engaged in the same profession.

The abstraction is that the output and service doesn't matter. It doesn't matter to the character, nor to the location where the profession was practiced. Because it doesn't matter, we're free to imagine that the output or service was anything we want. The blacksmith spent the week crafting a masterwork item for a noble. The noble paid up front, but there were cost overruns, and the blacksmith even had to pay a local with Profession: Alchemist to give him a potion that would keep him awake. At the end of the week, the blacksmith had a total profit of 1d20/2 + half his skill modifier in gp, and he had a masterwork sword, which was handed over to the noble. Or stolen. Or lost. Or whatever.

The blacksmith could even work directly with the PCs. He might sell them a masterwork sword for however much it would go for. But, insofar as it matters to the game, at the end of the week that blacksmith's profit would be 1d20/2 + half his skill modifier in gp.

Why doesn't a PC just take ranks in blacksmith, make a bunch of swords in a week and supplement his Profession: Blacksmith income with the sale of all those swords? Well, mainly because he already had to sell those swords as part of the Profession roll, but also because what that plan calls for is a Profession: Salesman roll, with the paltry number of GP that entails for another week's work.

[LibraryOgre]

Tuckers Kobolds was a couple of Editions ago. And it does not account for optimization.

Once the PC's are 10th level or so in Editions like 3.5E, anything mundane is a bit pointless. Burning oil? Oh, like 1d4 damage? Smoke: ok make a save vs DC 15 with your plus 15. And teleporting past/away from things.

Not to mention that the under 1 CR foes have no chance of hitting a 10th level character unless they roll a 20.

To do Tuckers Kobolds in 3.5E, you need to up the power level of the kobolds.

a) I seldom talk about 3.x. 3.x is irrelevant to 90% of the conversation of "how competent should NPCs be", because not every game is 3.x.

b) At this point, 3.x *is* "a couple of editions ago." Tucker's Kobolds remains remarkably relevant for the current edition of Hackmaster, the current printing of Castles and Crusades, and pretty damn scary in Palladium Fantasy.

How would Tucker's Kobolds be relevant in 3.x? Pretty simple... by making them 10th level kobolds, which isn't a power boost... it's an assumed part of the world that there are leveled kobolds. Otherwise, all your dwarf and gnome PCs are getting a massive power boost over their MM stats, which is for a mere 1st level warrior.

If I didn't want to level my kobolds extensively? Give them NPC wealth by level... in wands. A bunch of 1st level kobold sorcerers with 3rd level spells in 1 charge wands. Take a tribe of 400 1st level kobold sorcerers, with 20 3rd level sergeants, 2 5th level lieutenants, and 1 8th level leader. Now, as 1st level sorcerers, they can all have a wand with a single 3rd level spell (cast at 5th level) and a single 1st level potion, and a single 1st level scroll... along with a club and a sling, which are free simple weapons. If you insist on making them warriors, we give them all the arcane schooling feat, and give each group of 4 one wand and three 1st level scrolls.

SCORES of kobolds attacking from concealment, ripping you apart with magic. Over the course of the day, you're faced with a scores of fireballs and lightning bolts. Flights of magic missiles. Showers of sling stones, thrown from behind Wind Walls or even silent images of walls (thrown either by every kobold sorcerer, or by those few sergeants, who have even better magic items). At this point, you're not dealing with their to-hit rolls... they're simply functioning as a matter of statistics. This says nothing of mundane traps, rock falls, tiny scamper holes... leveraging the 1 EL budget for all its worth.

THAT's Tucker's Kobolds in 3.x. Sure, you'll kill a lot. You might even win the day, because, after all, they have crap saves and almost no HP. But every time you waste a spell on a group of 4 kobolds with a wand, that 8th level leader makes a mark on the wall. And once he has enough marks, he sends six groups, instead of one. They eat you with numbers and spending their money well.

[Susano-wo]

Ah, the classic sound of condescension. Hopefully you didn't mean it that way.

No, it wasnt meant to be condescending; I should have used different wording. My apologies

Oh, okay. Profession: Specially Trained Blacksmith.

Blacksmith the is the profession, specially trained is just a description. Just like its unreasonable to assume profession: any, or profession: miracle worker, its unreasonable to try to take profession to duplicate crafting when they are explicitly different. from the SRD: "Craft skill represents ability in creating or making an item, a Profession skill represents an aptitude in a vocation requiring a broader range of less specific knowledge." Which might mean, now that I think about it, that by RAW anything you can take crafting for you cannot take as a profession, which solves the discrepancy right there, though economically it is silly, but it was already silly to assume every profession makes the same amount of money

Useful weapons, quality clothing, or anything else in a D&D game comes from somewhere. Normally where it comes from doesn't matter, but it's plausible to imagine such an NPC having ranks in a Profession skill. The Profession skill contains everything necessary to work in that profession. It doesn't address actual output or services rendered, but of course the NPC does have output or did perform a service. So would a PC engaged in the same profession.

The abstraction is that the output and service doesn't matter. It doesn't matter to the character, nor to the location where the profession was practiced. Because it doesn't matter, we're free to imagine that the output or service was anything we want. The blacksmith spent the week crafting a masterwork item for a noble. The noble paid up front, but there were cost overruns, and the blacksmith even had to pay a local with Profession: Alchemist to give him a potion that would keep him awake. At the end of the week, the blacksmith had a total profit of 1d20/2 + half his skill modifier in gp, and he had a masterwork sword, which was handed over to the noble. Or stolen. Or lost. Or whatever.

The blacksmith could even work directly with the PCs. He might sell them a masterwork sword for however much it would go for. But, insofar as it matters to the game, at the end of the week that blacksmith's profit would be 1d20/2 + half his skill modifier in gp.

Why doesn't a PC just take ranks in blacksmith, make a bunch of swords in a week and supplement his Profession: Blacksmith income with the sale of all those swords? Well, mainly because he already had to sell those swords as part of the Profession roll, but also because what that plan calls for is a Profession: Salesman roll, with the paltry number of GP that entails for another week's work.

Sure, if you make a profession roll, it is certainly fair to say that you used your product to make your money. I guess that's a way to solve the discrepancy as well. Well, no that doesn't work, because as a character who can create a masterwork sword, it doesn't make sense that you can make it and sell it, but not just make it. Which makes craft useless, which is why I think they intended for profession to be a catchall for things that are not performances or crafts, but that people would be trained in.

[neonchameleon]

What's the setting, what's the tone of the game? What are the NPCs there for?

[Frozen_Feet]

Related question, possibly.

What would be the equivalent skill level for DnD ranks?

For example, playing WOD games and in those, having 1 dot in something means poor and 2 is average, with the maximum in the realm of human ability capping at 5.

What's the equivalent in skill ranks for ability in D20 skill rank system? would it be 10 considered average with 20 being the best possible without magic?

The reason I ask is that I don't want to have a noble who has spent the entirety of his life in and around the upper-crust of society and his ranks in Knowledge Nobility amounts to "average/below average".

As FlickerDart noted, skill ranks are not the be-all-end-all of character ability in D&D 3.x. You also want to take a long look at character abilities, race, class, feats and flaws, representing various other facets of the character than just their vocational training.

Anyone looking to make an actual living out of a skill would place minimum of 4 ranks in one, as that's the maximum amount you can allocate to a class skill at 1st level. 1st level, as demonstrated by starting age tables, represents a young adult fresh out of training. A specialist would want to keep a skill maxed at every level, and other skills at maybe half the maximum ranks; this is the default assumption of the d20 system, and enforced by the rules for non-class skills.

Now, as for the total modifier: d20 system works in increments of five. The basic difficulty classes can be found here. As Flickerdart suggested, a modifier of +5 is bare minimum for anyone to be considered "expert" in a skill, as it allows for automatic passing of Easy checks in all cases, and automatic passing for Average and Tough check when taking 10, and even in a hurried or risky situation a character will succeed 75% and 50% of time. It should be noted that specific rules for skills are pretty extensive, so often, knowing just the modifier will not be enough to tell you what it would translate to in a real situation. For example, the Jump skill has a table telling you how much height and distance you can reach by passing various checks. So instead of saying "+5 modifier is pretty good", you'd first look at the modifier, then at the table telling you how far the character can jump, and then cross-reference the results with real-life statistics on jumping.

[LibraryOgre]

My rule of thumb for level is Age/10 is your level (for humans). As such, I'd say that, training-wise, 4 represents an apprentice (competent, but not really able to function on their own), 5 a journeyman (able to function on your own, start to be able to apply your knowledge to other areas [synergies]), and 6 or higher goes into the Master level.... fully competent, and getting better.

As mentioned, these are just the ranks. You're still going to have to deal with the modifiers. I'd say that, at first level, you're likely looking at average people having +8 in their main profession... 4 ranks, 1 stat, 3 from a skill focus. By 4th level (a human in their 40s), those who are pretty good are likely to be looking at +14-+15... 7 ranks, 3 from a skill focus, 2 or 3 from attribute increases (+1 at 4th level, +1 to Int and Wisdom from Middle Age, maybe kicking you up to a 16), and 2 from a masterwork tool.

I think, when you expand into the broader world described by 3.x mechanics, there's a lot that wasn't covered (because it's not relevant to most D&D games, much like I tend to assume there's spells for fertility and childbirth and the like that aren't covered by the books). If I wanted to write Shopkeepers and Surplus Inventory on a d20 based system, I'd include synergies. Your "Blacksmith" gets a synergy bonus to his income check if he also has 5 ranks in Weaponsmithing and/or Armorsmithing, because, while he mostly deals in horseshoes, nails, and pots, he can turn a bit of money fixing armor or touching up blades. He also gets a synergy bonus from Appraise and Profession: Shopkeeper (or Profession: Blacksmith), not because they help him make better pots, but because they help him run his business better... Appraise means he makes shrewder deals for things he buys, and Profession means he wastes less money.

So, while this 40 year old, 4th level blacksmith may make items with a +14, he rolls for his income with something like a +20... that +14 for his craft skill, and various synergies that make him a better merchant. That means that unwise craftsman, with points spread all over the place and poorly optimized (for his purposes) feat selections might be making about 12gp per week, the one who is well-optimized is making 15gp per week. And while adventurers may scoff and fart out 15gp tips, to a merchant that means an additional 156gp a year. It's a 25% raise over his less-optimized peer, at doing the thing he actually is trying to do with his skill check... make money.

[Citrakayah]

A sufficiently ingenious bunch of kobolds could do a TPK of high-level characters. Yes, even if they aren't high levels. Because they don't need high-powered scrolls, spells, or wands. In fact, they don't need magic at all. No, what they need is:

* a really big network of tunnels to call home
* basic engineering skills

Sure, you can wipe out some of them. Maybe even a bunch of them. But when every few minutes you end up running into a pressure-triggered plate that sends thousands of tiny darts at you (and yes, you have to make saving throws for the poison coating each individually), when trip wires set off a chain reaction igniting alchemist's fire traps that send the entire ceiling collapsing in on you, when you have to swim through banana oil (yes, banana oil) and are attacked by thousands of bees, when you have to walk across entire floors made of carefully arranged mica plates that break if a fighter in heavy metal armor goes stomping across them?

At that point it becomes a question of how long you can keep going. And the answer is: "Not as long as the kobolds. Give up and go home."

These are incredibly fast-breeding, small creatures with metabolisms that are very slow (reptilian, you know). They are extremely social, gather in ridiculously large groups, and prefer to hollow out large rock formations... most of the tunnels aren't large enough to let you pass, I might add.

If you are fighting kobolds on their home turf once they're entrenched, you have already lost.