Nøkk

The Nøkk is a magical spirit that represents water. It was one of the four elemental spirits that Elsa awakens in the Enchanted Forest.

History
The Nøkk plays with one of the Arendellian soldiers, until, the spirits became angered by the fighting, with water, along with fire, disappearing from Arendelle. The Nøkk also frightened Olaf when he was alone in the woods.

Elsa tamed the Nøkk and used it to cross the Dark Sea. He left her at the edge of Ahtohallan. The Nøkk saved Elsa when she unfroze and fell into a pool of water below Ahtohallan, and carried her back to Arendelle just in time for her to stop its destruction by the large wave. After Arendelle was saved, the Nøkk returned Elsa to the shore by Enchanted Forest before dissipating into the water.

During her time in the Enchanted Forest, Elsa froze the Nøkk so that it was able to traverse land. The pair then ventured across the now frozen Dark Sea back to Ahtohallan.

Personality
At first the Nøkk was very distrusting and aggressive. It hampered Elsa's attempt to cross the Dark Sea, and even tried to drown her. His temperament completely changed after Elsa tamed him. From then on the water spirit was placid, and served Elsa in taking her where she needed to go. The Nøkk went so far as to rescue Elsa after she emerged from Ahtohallan, and then took her to save Arendelle.

Abilities

 * Water powers
 * Very high speed, endurance and strength

Elsa
At first, before taming, he tries to drown her, but after she tames him, he saves her and helps her save Arendelle. Later she rides on his back, also on dry land thanks to her ice powers.

Trivia

 * The Nøkk appears in Scandinavian folklore. It tricks people, or can be tricked, and it is said that when a rider climbs onto its back they are unable to get off; when the spirit returns to the water they are therefore drowned.
 * It took six months of development to complete the Nøkk for Frozen II.