(I was always thinking of cobalt when I heard Nethack talking of Kobolds...)
Kobolds in fantasy games are often amusing little creatures, and surprisingly varied from setting to setting. Well, the only common things that can be said is "amusing" and "little". They're one of the fantasy "staple" races, most often in the role of cannon fodder. As seen, they range from evil dogmen to humanlike comical idiots... all in all, the games probably wouldn't feel quite the same without them. Absolutely adorable little folks. (However, I prefer to like them from distance.)
Kobolds in (A)D&D (And most other FRPGs)
In Dungeons & Dragons and its immediate progeny, Kobolds have some canine bits in them, and some humanoid bits, and also reptile bits.
Some recent art in Neverwinter Nights (based on the new D&D 3rd ed.) shocked people a great deal - most people had got used to the idea that kobolds are above all dog-like in appearance, or at very least in sound, but apparently the reptilian bit has been there at least since AD&D 2nd edition and perharps even far earlier (for example, my D&D Classic Rules Cyclopedia from 1991 mentions "scaly, rust-brown skin"), and is now very much emphasised in the new edition! Opinions in gaming circles are split, but kobolds are still kobolds.
So, in the most recent incarnations of D&D (The 3rd edition, and the Open Gaming Foundation's SRD), the kobolds are little rustyish-grayish reptilian humanoids, with only remotely canine sound in their language (they speak Draconic; former editions recognized Kobold language as language of its own). The Neverwinter Nights website described them pretty accurately as "Attack Geckoes".
Kobolds live in darkness, don't have much talent on fashion side (no, they got a new edition and look, but they still can't afford decent clothes!). They prefer to attack in numbers from distance, often with tricks and well laid traps helping them, due to their weakness as individuals and their less well defined hand-to-hand combat - they are fearsomely accurate crossbow users, and if they have to go forth in melee, they use half-spears. And as said, they like traps. A lot.
They fill the ecological and political niche right below goblinoids and orcs, and can often be found not far from them - some suggest they're actually relatives, an assumption which may have had some basis before, but due to this new-found reptilian nature it is hard to believe - and I could not find a mention of this in the game references, either, not even the older ones, but they do share the same sort of function as orcs. Kobolds dislike other humanoid or fey races, some really really much (gnomes, spirits, and - if I'm to believe Nethack - elves, for example, fall in this group).
Kobold favored class is sorcerer, mostly because kobolds like to believe they are descended from dragons.
(Personally, I don't care whether they're canine or lizards, because I like both wolves and dragons. =)
While many fantasy games still do describe kobolds as anthro-canids, GURPS Fantasy Folk source book has another kind of kobolds, probably putting them closer to German household sprit origin, but on the way there, sort of tosses them out of the wagon to the wayside and lets them walk to the destination. And they sort of try to walk back where they came from.
GURPS kobolds are smallish blueish-skinned humanoids, definitely not of spiritual origin. They are the "obligatory race of funny little idiots", often comdemned to slavery in societies of more intelligent races (even orcs seem bright compared to them). They have generally low intelligence, very short attention span, and definite urge to do practical jokes at every turn - but they are also simultaneously very easily offended and don't take criticism or jokes aimed at them too well. The kobolds live either in bands in wilderness robbing unsuspecting travellers in numbers (though something as simple as shoting "Look, Bigfoot!", pointing at one direction, and running to other, is often found to be a great protection in case of kobold assault), or as thieves, or, more often, in service or as slavery in areas populated by other races. They sometimes breed so fast that they overrun cities and eat food stocks, which is why the kobold quarters are often purged of unwanted individuals by the authorities.
- http://nwn.bioware.com/builders/creature_profile1.html - Neverwinter Nights profile of Kobolds
- http://www.opengamingfoundation.org/srd/srdmonstersijk.html - Monsters, section I,J,K. System Reference Document. published by the Open Gaming Foundation.
- GURPS Fantasy Folk, 2nd ed., Steve Jackson Games 1995. ISBN 1-55634-309-4.
- http://advancedkid.narod.ru/mm00178.htm - Kobolds. This is probably from AD&D 2nd ed. Monstrous Manual.
- Dungeons & Dragons Game Rules Cyclopedia, TSR Inc, 1991. ISBN 1-56076-085-0.