From Dragon Eye Atlas
The height of a child but the size and weight of a blacksmith, that is the average dwarf. An adult dwarf is most often somewhere between 120 and 150 cm high but weighs 80 to 120 kg. And yes, much of that actually is heavy bones, because dwarves are adapted to smashing stones and digging ore, though it is unclear if their bodies slowly changed over milennia of digging or if they started digging because their bodies were so suitable for it.
They are without a doubt the first race to have discovered the art of metalworking and are still the most adapt in it, thanks to thousands of years of experience and countless secrets of the craft passed on only orally from one dwarven master forger to the next.
Dwarves are also adapted to underground life in other ways. They are fine with low air quality that would make most humans choke, and are not very sensitive to bad smells, with the exception of toxic or dangerous gases as can build up in a mine, they do have a very good nose for those. They can also see very well with very little light. An old lantern or torch is enough to illuminate a tunnel for them as if it were daylight. On the downside, their hearing and vision at long distances is not well developed and when they are in the open countryside, most things near the horizon appear quite blurry - possibly one reason why many dwarves do not like the outdoors much.
Dwarven culture seems similar to humans at first glance, with their kings and crafting guilds, but that is a mistaken assumption. There is actually a completely different social structure behind dwarven society, that has nothing in common with feudalism.
Dwarves have specific roles within their societies, which are typically small and concrete, not political like human realms. Most dwarven strongholds are independent entities. Dwarven kingdoms are simply a number of strongholds joining together under one leader, but aside from outside representation and a joining of military forces, not much union is to be found. In fact, a dwarven king is more like a general than even a human duke.
Positions within dwarven society are based on merit and merit alone, from the lowest garbage collector to the king. The pride of a dwarf is in his field, and the respect other dwarves pay him is based on his capabilities in his assigned duties. A capable mushroom farmer can easily be more proud and more respected than a king who does not live up to expectations. Dwarves never respect a title or a position, only the one holding it and only if he holds it well. It is, in fact, quite common for dwarven kings or leaders of strongholds to be peacefully removed because someone else appears to be more capable at the job. Obviously, no titles within dwarven society are heritable, though some families pride themselves on having successfully trained successive generations to earn the same title again and again.
Most dwarven strongholds are close-knit societies and not welcoming of outsiders, though they are rarely openly hostile. Rather, a visitor will find himself faced with hospitality and a stoic wall of silence to any more personal inquiries. For hundreds of years, humans knew next to nothing about dwarves because they simply didn’t talk about themselves beyond surface courtesies.
But with the end of the dwarven kingdoms and the dominance of human realms, many dwarves are now living within human towns and cities and while traditionalists within dwarven society bad-mouth them as soft and weaklings, city dwarves have become somewhat more friendly and open.
Dwarves only show a limited set of emotions openly, reserving many expressions for family and close friends. They are quick to anger and open with it, but joy and laughter are shown only in the company of friends or relatives. A dwarf will never show a positive emotion like that on the battlefield, for example, even if he just defeated a powerful opponent. Anger and aggression are only emotions that should be visible during or after combat, if at all. But afterwards, in the tavern or the drinking hall of his stronghold, all that joy and satisfaction will come out. And then there is the issue of female dwarves. Countless myths circulate among humans about this topic, most of them conflicting and almost all of them entirely fabricated. The simple truth of the matter is that female dwarves grow beards as well and their breasts are hard to make out due to the typical dwarven body shape and choice of clothes. And outsiders never notice two dwarves being a couple because affection is one of those emotions that dwarves only show when no outsiders are present.
Like everyone else in a dwarven society, men and women have specific roles. Which ones varies from dwarven culture to culture. A common example is that working with stone is work for men while working with wood is work for women. Both of them would be deeply insulted if those things are confused - asking a female dwarf if she is a stonemason is as likely to result in trouble as asking a male dwarf if he is a carpenter.
Dwarves spend large parts of their life underground and have developed excellent low-light vision. This is not thermal vision, and in complete darkness a dwarf is just as blind as a human. But as long as there is even a faint light source, dwarves can see very well.
Further Information about Dwarves
Dwarves have developed special methods to grow food without sunlight, called Underground Farming.
That is not to say that they do not have daylight. Many dwarven cities have shafts of sunlight from natural or artificial openings, and they are put to use to grow regular crops as well. But Underground Farming is the larger producer by far in most cities.
Most dwarves follow the Dwarven Ancestors not-quite-religion, though some dwarves that have lived among humans for a long time are known to follow human religions. There aren't really any temples for these ancestors, but the Ancient Dwarf Statues are impressive monuments built in their memory.
Even when living within human society, dwarves use their homelands dwarven laws among themselves. They marry according to dwarven laws and customs, they resolve disputes in front of a dwarven judge, they trade according to dwarven trading laws. With humans, gnomes and others they will use the law of the land, of course.