The Human Race
Physiology
The average Human stands between 5 1/2 and 6 feet tall, with skin that covers a wide range of shades of brown and beige. Human hair ranges from black and brown, to lighter shades of blonde and reddish-orange.
Human sport a wide variety of hairstyles, but usually the men prefer shorter hair, while the women tend to wear theirs longer. Human men often sport facial hair as well, but they tend to keep it fairly trimmed, unlike Dwarves. Some choose to go completely clean-shaven.
Mythology
Before the dawn of humanity, the Lords of Heaven resolved to fashion a body of flesh, each according to his own desires and purpose, for together they had forged the mortal soul to inhabit the world.
Now, while the gods troubled themselves with clever schemes and wise doctrines, with which to create their children, Hedakir, youngest of the Lords of Heaven, saw the folly of their ways, saying to himself,
"My brothers seek to craft ideals and philosophies for the soul to inhabit, for they are old and set in their ways. Only by flesh may one inhabit the world, so must our children be made of flesh! I will fashion a body from the flesh of the beasts and gift it with the soul we have created!"
So Hedakir fashioned such bodies. From bone, breath, and blood, he fashioned them, and he also bound to each a soul, giving it life and will. And so he called his creations "human" and said to them,
"Expand and multiply! Spread to every land and make it your own, for the world is wild and must be subjugated!"
And to his brothers he said,
"Bear witness, old fools, for one does not inhabit the world, but by bone, breath, and blood! Forsake the old things, and embrace these new ways, lest my children take all lands for their own!"
And so, many of his brothers were filled with jealousy and they plotted against him and his children.
-- The Codex of Origins, Chapter 2
Society
Humans are a malleable race in general, so their society is heavily influenced by their environment. Since Hedakir created them to fill the world, humans are the most adaptable of any race. Their societies exist in a perpetual state of flux, moving from one big thing, to the next big thing, making discoveries, testing new ideas, creating movements, and so on.
The one thing that unifies humanity is the drive to seek out new things. Human kingdoms are always looking to settle new territory and expand their knowledge, which sometimes causes tension with other races. The 'misunderstandings' that humans have had with other races are legendary, and have sparked more than a few multi-generational wars. This isn't helped by the fact that the creator deities of many races despise humanity, and have imparted that mentality to their creations.
Warfare
Like everything else in their society, warfare is a complex and ever-changing thing for humans. Combat leaders are always altering plans and changing tactics, which makes them unpredictable opponents to say the least. Leading humans in battle is like herding cats, however, and sowing disorganization in the ranks can cripple a human military.
The front lines of a human military are almost exclusively men, in both direct combat and supportive roles. The females usually can't keep up with the rigors of warfare, but anyone with sufficient sorcerous or divine power is a welcome addition, male or female.