|~ Hans' now infamous first warning of the trolls in film|
Trolls appear as the main antagonists of the Norwegian horror "Troll Hunter" and are based on the Trolls of Norse legend, being much larger than humans and acting akin to semi-intelligent but aggressive animals - they are also a collective term for many connected species (just as in mythology).
The most prominent trolls in the film were the 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.
Behavior and Traits
Much like their mythical counterparts, Trolls in film are semi-sapient race of humanoid giants whom aggressive and also collective terms for many connected species. Trolls in film indeed vary in appearance and sizes, but all of them extremely weak against sunlight that can petrify them.
In terms of behavior in general, trolls are normally short-tempered, aggressive and not so intelligent beasts as everyone knows it. A blend of science in the otherwise fantastical film revealed that should any of them infected by rabies, trolls would increasingly become violent and bold berserkers whom not only resulting them more dangerous than usual, but also wandered too far from their territory that would've exposed their kind's existence to the public and causes mass hysteria. Although, no matter whether they behave normally or become berserker due to rabies, nothing is angered them more than anything but smell of Christians blood: Should they smell a nearby Christian, they would immediately went into berserker fury - this was explained by the director of the movie in the sense that Trolls see Christians as invaders who stole the reverence and worship the Norse used to have of Trolls and forced 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 ire for the already short-tempered beasts).
According to titular "Troll Hunter" Hans, modern science revealed why trolls in that film would petrify upon contact with sunlight: Trolls' body is incapable to convert Vitamin D in ultraviolet light within sunlight to Calcium, and contact with sunlight would trigger violent chain reaction within their body. 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. From this statement, trolls' suspectibility to petrify by sunlight is true, but not accurate as they are calcify into solid bone instead of literally turned into rock statues. That's why Hans armed himself with UV-emitters that can simulate sunlight against these beasts.
Trolls Found in The Film
The Three-Headed Giant aka. Tusseladd was one of the first trolls encountered by the group and towered over an ordinary human, to the point its heads brushed against the tops of large pine trees - like most trolls it was semi-intelligent but also extremely feral (later explained as a side-effect of rabies).
The Three-Headed Giant chased after Hans and the group until Hans managed to petrify the troll using his light, which mimicked the properties of sunlight as the light was ultraviolet beam - this resulted in the Three-Headed Giant turning into a stone-like statue (in reality it was solid bone).
When asked about the nature of the Three-Headed Giant Hans explained that it was not born with multiple heads but earned them with age, he also claimed the extra heads were not true heads but rather used to intimidate other trolls and attract females.
The Three-Headed Giant is a reference to the Ettin of folklore and popular fantasy.
Unidentified Forest Troll
RaglefanThe next trolls that Hans and protagonist encountered is a Raglefan, whom encountered on the bridge. After the fight against this particular troll, Hans took some sample of its blood so his fellow TSS study it and later, uncovered that rabies has caused the trolls' aggressive behavior.
DovregubbarDovregubbars are the next trolls to be encountered. When Hans and the crew is trapped within a cave inhabited by a pack of these trolls, the trolls somehow went ballistic than they supposed to be. By this point, Kalle finally reveals that he's Christian that provoked the trolls to went ballistic. The group is forced to leave the cave in great haste, but Kalle is captured and killed. The rest of the group is left distraught and now even more determined to expose the truth.
The Jotun was the largest and most powerful troll in the movie and served as the climatic villain, it is based on the ice giants of Norse mythology and stood at roughly 200 ft in height, easily dwarving every other troll in the movie. A rabies-infected jotun is revealed to be the main cause of trolls become scattered from their habitat. Due to the problems that Jotun caused as it would indirectly rally the frightened trolls to attack human populate, Hans ultimately petrified the troll.