Frozen 2 & The Fairy Mythology

Frozen 2 gets a shocking amount about lore right, or at least proximal to right.

If you haven't seen the film than be warned, there are potential

Spoilers Ahead.

Frozen 2 nailed the idea that tutelary beings (spirit owners and protectors of the land) will at times become poltergeist like when they see violence. In Iceland the spirits that dwell within a cluster of rocks become dangerous when the see a man get murdered, such that no one can safely go near those rocks. Fairies/nature spirits are extremely sensitive, and prone to changing into wild beings when they become upset. Some of them even go so far as to change shape when they grow angry. Building a home or bridge on the property of these spirits, especially without a sacrifice to them, could also lead them to become destructive. They were after all the original owners of the land, and disliked having their homes disrupted. 

One aspect of the lore of land spirits that Frozen 2 doesn't touch on is the notion that the spirits of the land often depended on humanity for their very survival and so often wanted people to build certain things on their land. For example, the hulde of Aurland attacked any building people tried to build on a hill, pulling the buildings down and tormenting animals and people in them. However, they did allow people to grow hay on these hills, as the fairies needed hay for their own cattle, and milk from human cattle (Flom, 1949). There are similar reasons for nature spirits to have been pro mill, dam, and the like. This isn't to say that they always wanted these thing constructed. Though they usually did something about construction or gave some sign during the construction if it upset them. There are many stories of people trying to build buildings, only to realize that they needed to build these buildings elsewhere, because the fairies kept stopping the construction by moving the stones, breaking the equipment, etc. There were, of course, people who didn't take the hint, and typically these people and their families were very specifically punished. Of course, fairies might also choose to haunt the house after this instead. 

Another interesting piece fairy lore that Frozen 2 got right-ish, was the notion that one could calm wild spirits by defeating them. Fairies, spirits, Japanese kami, and more were in essence tamable beings. People often tamed them through veneration and celebration, but sometimes heroes needed to step in and defeat them so that they could calm down. Of course, overcoming the spirits, giants, and other beings of lore rarely changed them as quickly as "Frozen 2" depicted, but it was still nice to see this idea on screen. Some of the only other times I've seen it depicted was in "Moana" and "The Spiderwick Chronicles" 

Salamanders and Water Spirits

As with Frozen 2, in European lore one of the most common forms for water spirits to take is that of a horse. The horse in general seemed to symbolize the deities of the water. Poseidon in Greek Lore was god of the ocean and horses, for example. In Japanese lore the water kappa were connected with horses as well. Ishida Eiichiro drew parallels between the kappa and the water deities throughout Eurasia, specifically discussing the fact that water deities have a tendency to be connected with horses and afraid of iron. 

Less commonly attested to is the notion of salamander. There was an idea repeatedly presented that there were magical lizard/salamander like beings who could magically put out fires, came from fires, or were the product of fire. 

Wind was an interesting character in Germanic and Nordic fairy tales, but it was also one that is hard to pin down, because it appeared with different personalities in different fairy tales. In one story the wind keeps stealing a man's lunch and so the man goes off to confront it. As it turns out, the wind was mischievous, and generally unaware in the way a child might be, so the wind felt guilty when it realized it had been hurting the man. In other tales the wind would act like a crotchety old man, yet one with romantic notions of love, for it would help women seeking those they loved. 

I discuss the trolls from Frozen 1 who make another appearance in Frozen 2. One additional aspect of their nature I should mention, however, is that even Odin, god of wisdom, often sought the fortune telling powers of land spirits and shamanesses. 

http://fairies.zeluna.net/2014/09/snow-queens-trolls-and-frozen.html