OOC-I am not just putting my own ideas into this post, but I've decided to use some of the ideas of others as well.
IC-The Dryad is thought be many of those who have never seen one to be a beautiful & often friendly maiden, but whilst there is a grain of truth in this, there is far more to it.
Dryads are "made" in several ways. Some are the souls of those honest Rangers and Druids who die a violent death in the forest in the act of defending it against lumberjacks and others who would destroy it. The body, after being buried, is reanimated as a Dryad by the earth surrounding it, which then opens to allow the new Dryad out.
There are those few who are "turned" by another Dryad as an act of deep love.Indeed, it can only be done as a genuine love act, when the Dryad loves a human so much that she wishes to spend her whole life with that person. The Dryad bites the person in the throat,kills him or her, and then uses her love and the magic in the forest to change the person into a Dryad like herself.
All Dryads are female regardless of the fact that many,perhaps most, used to be male.As they remember their former lives, lesbianism is common amongst them because if they as males were romanticly intrested in women, this does not change just because they are now female.
There are rumours of Druids using powerful magic to turn themselves into Dryads,and even of a type of tree that can enslave a person, but neither rumour has so far been proved.
How muscular a Dryad is depends on her life span. A newly created Dryad will be as weak as a small child for a few days, before gaining the strength of a young woman for her first century. Every century a Dryad lives for the first thousand years, she grows stronger. So a thousand-year-old Dryad would be very strong indeed.Few are anywhere near that age,although there are some with the strength of men.
A Dryad can move through the earth and through living trees, but not through brick or dead wood or carved stone.A pavement would keep them out, but a forest path or a mountian would not.They can step out of the trees or the ground, but only for an hour at a time or they feel sick.And every two days they must return to the tree where their bodies *died* or they will die. So whilst not trapped inside their trees, they are tied to the area of them. If their tree is destroyed by axe or fire or by wind, they die within minites. Therefore they are very protective of their trees and of the forest in general, and will kill to protect their home tree.
If the home tree is damaged by iron (eg an axe) the Dryad is trapped inside until the wound in the bark heals, so most sleep near their trees instead of inside them.A Dryad *locked out* of her tree will not die but will become sicker and sicker and weaker and weaker until she can renter it.
They are few in number,too few to protect themselves against a sustained attack from a large number of attackers. They have wooden weapons such as spears with fungus tips that infect any wound given, wooden spikes and clubs, but their most common tactic in battle is to pull a person's hands and head into solid wood or rock and let them die of blood loss and suffocation.There are Dryads who have become tainted by evil magic and have killed any human who enters their section of forest but most Dryads only kill if they feel that they have to.