Having recently looked at the toughest of the five standard "evil tribal humanoids" of D&D, it's time to complete the set by looking at the weakest. The kobolds of D&D have, it's fair to say, generally been treated with ridicule. That's not because they're particularly silly (although there are enough examples of creatures that are), but because they're so puny: one of the very few creatures that are likely to lose to first level characters, even when they have them outnumbered. The intent may be to have even first level characters appear heroic by defeating larger bands of foes; the result has mainly been to make those foes laughable.
The word "kobold" is German, and refers to a sort of capricious or malevolent sprite, similar to goblins in English folklore. They are often household spirits, but are, perhaps, better known as evil spirits haunting mines and bringing rock collapses and toxic vapours down on hapless miners. It's almost certainly this conception that Gygax used as inspiration when he devised the race for the earliest edition of D&D.
1EUnlike the other evil humanoid races, kobolds are shown as being reptilian. They appear as slightly chubby humanoids with rusty-coloured, scaled, hairless skin and a rat-like tail. The head is doglike with pointed ears pressed flat to the skull, small horns above the eyes and a row of blunt spines running from the top of the scalp to the nape of the neck. They appear to have four fingers on each hand and three toes on each foot. They are, on average, a mere three feet tall, similar to a halfling, and quite a bit smaller than a goblin.
Statistically, kobolds form the bottom rung of the hierarchy of evil tribal races, and roughly tie with the giant rat for the honour of being the single weakest creature in the original Monster Manual. Compared with orcs, they have two fewer hit points, a 10% lower chance of landing a blow, a 5% higher chance of being struck in return, and do two fewer points of damage when they do hit. Given that even orcs are only equivalent to typical first level characters without any particular combat training, this is remarkably weak, and they only have half a hit die (or no hit dice and a handful of hit points, depending how you look at it).
They are nocturnal and often subterranean, and, like goblins and orcs, are demoralised in full sunlight. (Like almost everything else, of course, they don't actually need light to 'see', being able to detect living beings by their heat signature). They live in communities averaging 350 individuals, including the implicitly non-combatant females, who form only a third of the adult population. Where other tribal races tend to have surprisingly high numbers of infants at any one time, kobolds are the opposite, implying that they grow to adult size rapidly. On the other hand, they hatch from eggs, and the number of eggs far outweighs the number of hatched infants, so perhaps there's a particularly long incubation period. Or most of them never hatch, for whatever reason.
They have the same low intelligence as the other tribal races, but the average individual is nonetheless fluent in four different languages - unusually, though, we're told that a significant minority can only manage two. We're told that their tribes consist of war bands based on family descent, each of which must presumably maintain their own batch of eggs. They are, like most of the other tribes, "lawful evil", with the former half of that descriptor being illustrated by the fact that stronger tribes rule over weaker ones, implying the existence of larger, tributary political structures above the individual tribes.
They are sadistic and murderous, apparently killing for pleasure, and, while orcs hate elves and goblins hate dwarves, kobolds are said to reserve their strongest animosity for gnomes. Despite their hatred for "all life", they have domesticated wild boar to use as guard animals. They favour simple weapons, and don't seem to wear armour, but are also by far the longest lived of the evil tribal races, able to last well over a century if they don't get killed first.
2EThe appearance of kobolds has changed significantly by this edition. They are now remarkably skinny creatures with five elongated fingers on each hand and a much longer snout than before. Although they still seem to be reptilian in other respects, they have at least some hair, in the form of whiskers on the snout. The illustration seems to show that they still don't wear armour, although the statistics say otherwise (it's not very good armour, though) so perhaps this one isn't expecting a fight.
We're given a little more information on the nature of their society and the relative strength of their leaders, but this expands on, rather than clashing with, what went before. They do, however, now eat the flesh of humanoids, which is interesting, since orcs are now less likely to do so than in 1E. They apparently regularly war with goblins, as well as (implicitly) with gnomes.
It is, however, apparent that the writers have cottoned on to kobolds being regarded as a joke by players. They play up on their dog-like appearance in 1E by giving these versions yappy voices and the smell of wet dog hair (which again, makes one wonder how hairless they really are). Conversely, they also explain that kobolds are good at laying traps and using terrain to their advantage for ambushes and striking from concealment - which makes sense for any race so easily beaten in a fair fight. Some of them can even use magic, although there's no detail provided.
3EThe appearance of kobolds changes again in this edition. They now have a mottled patterning, four horns on the head, and a row of spiny tubercles above each eye. The head resembles that of a baby crocodile (both the whiskers of 2E and the mid-line crest of 1E have gone) and the feet are least semi-digitigrade, with the heel not reaching the ground.
Changes to the rule system mean that kobolds now have a single hit die, since this is the minimum for anything intelligent enough to have a character class. This is partially offset by a very low strength and physical resilience, but it's notable that they are now of fully human intelligence. Significantly, however, they are also shown to be more nimble than a human, which, combined with their small size, makes them harder to hit than orcs. Their armour is shown to be a combination of leather and a tough natural hide, and they are now given specific skills in stealth and trap-making, making explicit in rules terms the idea from 2E that they're supposed to rely on subterfuge rather than straight-up combat ability.
Kobold tribes now average only 220 adults plus a couple of dozen children (it's clear that, unlike orcs, both males and females are equally combat capable). This is less than in earlier editions, although still larger than orc or hobgoblin tribes have become. While the egg hatcheries are much smaller than before, they are still large enough to suggest a long incubation and/or high mortality - just not as much as they used to be. It's clarified that they merely hate other intelligent life, not just life in general, and they're omnivorous but with a taste for human flesh. They no longer have their own language, instead speaking Draconic.
In other respects, their culture and personality have changed little, and, unlike goblins and orcs, they retain the "lawful evil" descriptor.
5EIn 5th edition, kobolds, already the smallest of the five evil tribal races, have shrunk further; three feet is now their maximum height, not the average, with two-and-a-half being more typical. The image shows a being that actually looks quite muscular (for what that's worth when you're so small), and the horns are longer than before. In a reference back to 1E, they have four fingers on each hand, and three functional toes, plus a dew claw, on their feet, which are now even more fully digitigrade. They've stopped wearing armour again, and, protected by agility alone, have returned to being the least well-defended of the five races. While they do now have two hit dice, their hit points and typical weapon damage are remarkably low by the standards of 5E.
In other respects, their physical statistics remain low, apart from a high natural agility, but they have also lost intelligence and willpower making them now stupid as well as weak. They are the only race left of the five that still retains the sensitivity to sunlight, perhaps because they now more regularly live underground than in dark forests, which were previously implied to be at least equally likely. They do at least keep some domesticated animals, but no longer anything so impressive as giant boar, rats being more typical.
While the core rules say little about kobold society beyond the fact that they are now often found in service to dragons, Volo's Guide indicates that the original strong emphasis on family bloodlines has now gone. Instead, eggs are raised communally, so that kobolds don't even know or care about the identities of their parents. Like some fish, but unlike real-world reptiles, kobolds are apparently capable of changing sex, reinforcing the idea that the genders are equal in society - the fact that their eggs don't require much tendering would also help here, since nobody is kept out of a fight by virtue of pregnancy.
It seems likely that kobolds were originally intended in D&D to be scary little monsters than first level characters would find a challenge in numbers. Instead, they became a by-word for 'pathetically weak' and most of their history since then has been a reaction to that, either owning the humour, playing up the tendency to make deadly traps, or some combination of the two. Interestingly, Volo's Guide tries the tack of making them seem not all that evil, but instead pitiable, if mean-spirited and emotionally stunted, creatures that would really rather everyone else just stop bullying them.
Kobolds tend to get less attention in game world write-ups than orcs or goblinoids, probably because they aren't often seen as an interesting threat. Nonetheless, they are not entirely ignored. In Mystara, they control a small nation that holds its own against its neighbours. It's described as a republic, although clearly only in the sense that Syria is a republic in the modern world, and, while we don't know how their leader is appointed, it's a fair bet that the word "democratically" wouldn't feature in the answer if we did.
In Kalamar, kobolds control a small and isolated city state on a desert coastline. This, too, is apparently a republic, since the leader is titled "mayor", but it's unclear exactly how that works. Forgotten Realms makes the draconic ancestry of kobolds explicit, although, here, they speak a degraded variant of Draconic rather than the pure language itself. Kobolds in the setting have a strong affinity for magic, which does help make them a little more of a threat. According to Volo's Guide, a significant number of kobolds live peacefully in the sewers beneath human cities, helping to maintain them for the authorities and generally trying to avoid being noticed by anyone else.
The kobolds of Golarion/Pathfinder are more varied in colour than the default D&D sort, having any of the five colours of the evil dragons. Otherwise, they seem fairly similar, with well-organised tribes and a penchant for making traps. Since one major tribe lives in a subarctic region, however, they may be less cold-blooded than traditionally described.
Designing kobolds in other systems requires giving them a mix of decent, but not overly impressive, combat skills and crappy strength and physical resilience. If the former compensates too much for the latter, though, it might be worth toning down. On the other hand, they should have decent skills in trap-making, and possibly in stealth and other subterfuge. They should also have some sort of vulnerability to bright light, in the form of a combat penalty and perhaps a vision penalty, since this is an unusually universal part of their description.
It's perhaps worth noting though, that some systems may struggle to make kobolds quite as puny as they are intended to be in D&D, since, in a less cinematic milieu, an angry midget with a dagger would still be far from harmless. In the real world, people can, after all, die from a single stabbing, and some systems reflect that sort of thing.