Though most Trolls have been turned to serve the Dark Lord, unlike the Orcs they are not His by nature. Trolls are simply very large, powerful giants which are closely associated with a natural environment. If Trolls are in their element, they are wickedly difficult to kill. They draw strength from the natural world, and this enables them to heal quickly and shrug off wounds that would kill a normal human.
There are Trolls closely associated with forests or jungles, grassy hill-country, mountains, rivers and the sea. Troll coloration helps them hide themselves in their particular terrain, and the older a Troll is, the more like a tree, stone or mound of coral he appears.
A basic Troll is a 150pt racial template. Trolls are universally regarded as monstrous, and are known to eat other sapient beings. They are more intelligent than animals, and seem to have a language, but more than that is not known, and even that little bit of knowledge is hard-won.