Trolls are a type of Other Fairies. They are some of the largest fairies, and are considered non-sentient.
Trolls are large, apelike creatures covered in shaggy fur. Their forearms are larger than their legs, so they often lope like gorillas(knuckle-walking). Their limbs end in large claws and they have small, red eyes and pointed, long ears, adapted for extreme darkness. They have a very powerful sense of smell, which is good enough to allow a blinded and deafened Troll to survive on navigation by smell alone. One of their most notable features are their large tusks protruding from the lower jaw upward. These can be used to inject a potent venom into prey items. Trolls are also notable for the hair on their head forming destinctive "dredlocks". The largest trolls are over 10 feet in height. Trolls cannot conjure magic. They are some of the most aggressive and durable species on the planet.
Trolls sometimes end up on the surface, blasted up by the powerful thermals in the chute system after a flare. Upon reaching the surface, they are often driven insane by the presense of what they consider bright light, even though it may be as dim as the moonlight. They generally proceed to go on a rampage, killing anything in their path. They are, indeed, responsible for the cattle mutilation incidents that many Humans blamed on aliens. The LEP often recovers and subdues the Troll before it reaches Human settlements. However, there have been some incidents. Indeed, a Troll encounter in Italy proved to be the catlyst of the Artemis Fowl incident. LEP procedures reccomend engaging Trolls with large teams, heavy weapons and preferably air support. To attack one alone is to court death. However, during the Fowl Siege, the oversized Human known only as Butler was able to singlehandedly take down a fully grown Bull Troll, using an assortment of weapons, his own massive strength and a suit of medieval period armour. The security footage of the fight has since been used in LEP training courses as a show of how to take down a troll. Captain Short's tangle in Italy is used as an example of how not to do it.