(A joint chat collaboration by manfred, Redwick, MoonHunter, Siren_no_Orakio, EchoMirage, and that's hopefully all of them.)
The Garim are Dwarwes in their heart, but they could miss certain parts. The most troublesome to them is their propensity to violence. Make no mistake about it, they are legendary warriors, and rightly feared, but for all this they would prefer the peaceful solution... it's just, somehow, it always ends with a fight. High adreneline is their natural state - they are always excitable.
A Garim is a serious, contemplative Dwarf, suppressing that slight bent towards violence, failing sometimes. In essence, a Romulan/Vulcan mix, that wants to walk the Vulcan path. Peaceful people who don't want to fight (but are really good at it when they have to).
Their philosophy (needs more details...) teaches them the avoidence of violence. Some actually live in underground monasteries. Most live free, but have still xenophobic tendencies (contact with other races too often ends ugly). Also, it is easier to be isolated underground.
Strangely, this is compatible with the common look on the dwarf: most dwarwes that show up on the outside world, are misfits, most probably with a problem to control their anger, some try to subdue it, some not.
Note: most Garim do avoid alcohol for obvious reasons.
As for their relations to other races, they are rivals (but friendly) of the Elves, but have often problems with Humans, especially the miners.
Summary: short, pointy eared folks (fey), normally hyper kinetic, master crafters, making stone musical items and other cool things in metal and stone. They may have something undefinably elven about them. And with runes as their power source, they are a kind of Underground Druids (since true Druids used runes and were sage/philosophers/leader types).
Garim as FeyAncient legends speak of their enstragement with other Fey, the Elves. The Dwarwes felt a need to understand the -whole- of the mother (possible Gaian motif), not just the stuff that grows in a thin film on the surface.
Whatever happened back then, the Garim become distanced to the Fey world, and are more mortal now, more tied to the stones of the mortal realm; less ethereal than other fey.
But as they strive to transcend the instincts that bring them towards mortality, the more fey-like they become. Incidentally, the better they adhere to their philosophy/religion, the more powerful their mystical abilities. They may not neccesarily be powerful magicians, but they certainly have the glamour of the fey.
Warning: they also more bothered by cold iron then. Only the ones furthest away from their fey roots can use iron. (But other metals, like gold and silver, are fine.)
The Collar optionMost Garim wear a collar, a religious torq as a symbol for the beliefs, and to help diminish their drive. Marked with runes of emotion retardation, those that are "stronger" - better at suppressing their mortal side - need fewer runes on their collars. The "rune casters" (equivalent of moderate level priests) don't need the runes anymore. Outcasts could have no collar OR a rune on their forehead marking them as "OUT CAST" so they can't enter a keep.
Rune casting(Note: The
Runecaster class became another inspiration for the Garim.)
As they become more peaceful, and concentrated on the way of the world (closer to Fey) they actually learn to manipulate the shapes, becoming the rune casters.
Thus rune casters could be the sages/philosophical leaders (they may have normal priests besides).
Abilities include various smaller or bigger aids in the hard underground life - from mining to defense and warning.
A "high-level" ability of the runecasters (when they become really powerful and almost Fae), is to be able to change their own shape, to contort themselves into almost any shape to squeeze under bridges, through walls, through caves, etc.