A Troll is a creature that comes in many forms. There are two main types of trolls: The Forest Trolls and The Mountain Trolls. There are also many subspecies, like the Tosserlad, Ringlefinch, Dovregubben and Jotnar.
The trolls are predators and carnivores though it was stated by Hans that they can eat rocks and some vegetation. The most prominent trolls in the film were Forest Trolls, the cave trolls and the climatic Jotun. All of the trolls in the film are exceptionally dangerous beings with the strength and mass to kill humans with ease, though most seemed to prefer hunting animals or livestock when not exploring the remote areas of Norway. Another blend of science in the otherwise fantastical film was the explanation that the trolls of Norway were becoming increasingly violent and bold due to being infected with rabies.
The titular "Troll Hunter" Hans, pursues trolls that have strayed too close to human habitats and eliminates them using special lights designed to mimic the sun's radiation this causes a violent reaction in even the largest of trolls, seeming to turn them to stone (however unlike in the myths it is explained more as trolls turning into bone, due to calcium) - some trolls explode rather than petrify (such as the troll under the bridge and the cave trolls).
It is explained that this is due to their incapacity to convert Vitamin D in light to Calcium. This causes the younger trolls to explode because their stomachs expand and gasses are pushed into their intestines and veins. The older trolls turn to stone instead because their veins are too constricted so the expansion occurs in their bones and the troll calcifies completely in a matter of seconds. this has been stated to be extremely painful for the victim.
Trolls in the movie, again like mythology, could smell the blood of Christians and went into a berserker fury upon sensing them - this was explained by the director of the movie in the sense that Trolls see Christians as invaders who stole the land from the Norse who used to coexist with the Trolls and forced the said Trolls into the wilderness as a result (Trolls in mythology are also said to find the noise of bells to be painful, hence the church bells of traditional Christian churches were a source of discomfort for the already short-tempered beasts).
Types of trolls Edit
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the Ringlefinch is a smaller type of troll not being much taller than Hans . These trolls are not spoken about as much as the others but they seem to urinate when they feel ill/threatened like the troll in the movie itself (Doing this due to the rabies it had contracted from the Jotnar)
The Dovregubben or "Mountain Kings" are some of the smaller species of trolls. Their bodies are covered with brown hair.