Gnomes

Height: Average: 3'6"/105cm Range: 3'/90cm to 4'/120cm
Life stages:
Puberty 17
Marriage 25-40, average 35
Life Expectancy 88 (M)/110 (F).
Appearance: Like a shorter dwarf, with a larger nose and ears, and the beard or sideburns kept much shorter. Brown or reddish hair.
Relations with Other Races: Dwarves: Masters since ancient times.
Origin: A subspecies of dwarves who have been a largely non-interbreeding underclass for hundreds of generations.
Location: Underground throughout the continent; more recently out among humans in Koslin.

Gnomes are the servant and labouring class for the Dwarves. Evidence (such as their ability to interbreed) suggests that they are in fact the same race, though this is not an acceptable theory for most dwarves. There are extremely powerful taboos against interbreeding (on both sides), and those gnomes who break the taboo, even if forced, are likely to be exiled (or, in the case of a male gnome and a female dwarf, the gnome killed - probably by "accident" in the mines - and the child exposed once born).
The much lower life expectancy of male gnomes is because of the large number of accidents they are subject to, as the primary miners for the dwarves. Female gnomes are domestic servants and suffer a much lower mortality rate. Polygamy is therefore permitted to gnomes, although it is not for dwarves and is seen by the dwarves as evidence of the gnomes' moral inferiority (despite the idea having originated with the dwarves in order to keep the servant population up). They do not have the dwarf taboo against marriage within the same clan hold, since they generally remain in the Dwarf Holds where they were born unless they belong to traders.
Gnomes accompany dwarf caravans to do the work dwarves don't wish to do, such as setting up camp, cooking and cleaning. Some polygamous gnomes who travel in this way have wives in different dwarf clan holds, and this prevents the population from inbreeding too much. The wives may or may not be aware of each other's existence.
To dwarves, working with any form of organic material (apart from a few substances used in jewellery, like amber) is considered gnomes' work, and not a "craft". "Hard" organics, like wood, are the domain of male gnomes, "soft" organics, like leather or cloth (and all food preparation of any kind, except above ground) belong to female gnomes. Some female gnomes also paint artistically, using materials which are made for technical illustration; this is not considered by dwarves to be a skilled craft (otherwise gnome women wouldn't do it, would they?). Gnomes also do the heavy, unpleasant, dangerous or otherwise low-status work in the other crafts. Gnomes, regardless of their skill or experience, always have little influence in their craft as far as dwarves are concerned. They do not participate in the governance of the crafts in any way, but they do have leaders among themselves who act as foremen.
There have been occasional gnome uprisings over the centuries. In general, they are now treated reasonably well, given that they are still an underclass. Individual dwarves, however, are sometimes cruel to their gnome servants if unobserved (it is considered bad form to do so openly).
Gnomes are more useful if they are literate, numerate and know some craft skills and magic, so the dwarves provide them with an education, which, while rudimentary by dwarven standards, is reasonably good by the standards of most humans. This includes limited and quite specific magic to make them more useful in the rock-shifting and metal-forging industries.
Some have self-educated themselves further and become "troublemakers", agitating for equal standing.
Gnomes are practically never encountered out of dwarvish contexts, unless exiled (or escaped), until Gnome Day. It is possible for a gnome to be freed, thus becoming a "loosegnome", but they were still expected to work for dwarves. Victory's employment of loosegnomes was controversial and caused her to be ill thought of among conservative dwarves.
Culture
It is rude to refuse offered food in gnome culture, and if one has a table it's not appropriate to eat anywhere else.
One can be shunned for nonconformity, which is more or less a death sentence in many cases.

Gesture language
The gnomes have an extensive gesture language for talking in noisy conditions (and when they don't want to be overheard by dwarves).
They have a gesture game like rock-paper-scissors, and other gesture games.

A common gesture is a hand brushed past the ear on the same side, which means roughly, "I know, but what can you do?"