The Trolls are the children and worshippers of the Troll Gods. Typically, a Troll is between seven and nine feet tall, and are usually toward the upper end of that spectrum. (Ghwerig was the only shown exception to this, being both dwarfed and hunchbacked, which left him at slightly under seven feet tall). They are largely simian in their physique, having a similar overall bone structure to most humans and apes (a result of their common ancestors, the Dawn Men); however, a description in The Hidden City notes that they lack the "protruding muzzle" of most apes, having a rather flat face. Their limbs are also a great deal longer than human limbs, allowing them to move both more gracefully and far quicker than humans. Their greatest asset is (or was) their inability to die of old age, effectively meaning they had to be killed in battle.
The Trolls are fairly primitive compared to the other races, being closer to animals in both appearance and behavior than any other race. They do show some faint hints of sophistication, however, such as having a priesthood and a rudimentary theology. They are also highly moral, being highly disgusted by kidnapping, unwarranted killing, and other human social problems.
Humans and Trolls have fought and killed each other for millenia, and Aphrael had previously predicted that the Trolls would one day be exterminated due to their inability to change, but would take half of the human race with them. Due to her intervention during The Shining Ones, however, the Trolls were forbidden to ever kill another human and lost their immortality, effectively ensuring that the eons-old war between the two races came to an end and the Trolls would eventually undergo a relatively quiet extinction. As of the conclusion of The Tamuli, however, the Trolls were still alive and returned to Thalesia.