Northuldra

The Northuldra are an adventurous people who live within the Enchanted Forest near Arendelle. Though they possess no magic of their own, they are deeply connected to the magic of the forest and its element spirits - the wind spirit Gale, the fire spirit Bruni, the water spirit the Nokk and the Earth Giants. They were on friendly terms with the people of Arendelle, but a shocking betrayal led to conflict between the two peoples led to a contingent of both being trapped in the forest for over 30 years and all outside relations being cut off.

They are experts at hiding themselves in the forest and keep huge herds of reindeer.

Role in the film
Over thirty years previously, the Arendellian King Runeard led a contingent of Arendellians into the Enchanted Forest. His stated purpose was to maintain good relations between the two peoples and to present the Northuldrans with a gift - a dam which would strengthen their power. Secretly, however, King Runeard was fearful of all magic. He believed, quite wrongly, that any access to magic made a people too powerful and led them to believe that they could defy the will of a king. The dam, in fact, was secretly a ploy to drain the Northuldra's magic and their bond with the forest.

He instigated a conflict with the Northuldra, but conducted his actions in stealth, leading those of the Royal Guards, including Lieutenant Mattias, to believe that it was in fact the Northuldra who were responsible for the conflict. During the conflict, King Runeard murders the Northuldran leader and himself falls to his death during the fighting. The conflict angers the spirits of the forest, who run rampant and then a magical mist appears, creating a barrier that allows nobody to enter or leave the forest. However, the young Iduna rescues the Arendellian prince Agnarr and the two end up together in Arendelle, eventually giving birth to two daughters, Elsa and Anna, with Elsa possessing magic granted as a gift from the forest.

Growing up, Elsa and Anna were told a tale of the Enchanted Forest and a mysterious river by their mother and father and the song "All Is Found." After becoming the Queen of Arendelle, Elsa begins hearing a mysterious voice calling to her. When she tries to follow the voice, the spirits of the forest invade Arendelle, draining its resources. Elsa leads a contingent of herself, Anna, Olaf, Kristoff and Sven to the Enchanted Forest, where she uses her magic to get them past the magical mist. There, the group discovers the contingent from Arendelle and the Northuldra, who have been locked in a sort of stalemate for over 30 years, distrustful of each other, but not openly combative. They reveal who they are and eventually gain the trust of both groups. In honor of them, the Northuldra sing the song "Vuelie" and offer their aid. Through a long and perilous journey, the group discovers the truth behind the conflict of thirty years before. The forest is freed and Elsa remains behind with the Northuldra as the forest's fifth spirit.

Trivia

 * The mythology of the Northuldra draws heavily upon the culture of the real-life Sami people. For the creation of Frozen II, Disney signed a contract with the Sámi people to respectfully portray Sámi culture. The Sámi parliaments of Norway, Sweden and Finland, along with the Saami Council reached out to collaborate with the film's producers. The contract also included an agreement that Disney would produce a dubbed version of Frozen II in one Sámi language and participate in cross-learning initiatives that contribute to Indigenous communities in Scandinavia. The Sámi people and those worked with by the filmmakers appear in the film's credits.