WARNING: many, many spoilers
In many ways, Frozen and Frozen II are mirror images of one another. Anna is the protagonist of the first, and freezes to death; Elsa is the protagonist of the second, and freezes to death. The non-protagonist sister in each has one solo song (“Let It Go”, “The Next Right Thing”) during which they learn about themselves, and begin the process of letting go of that which they most fear and controlling their powers. Elsa learns, in Frozen, to allow Anna back into her life; Anna learns, in Frozen II, to allow Elsa to be truly free.
But that would mean that Anna has powers, which of course, she does: a superhuman capacity for love. Who else would’ve been so loyal to a sister who shut her out for 13 years? But if the two movies are mirror images of each other, then Frozen II must require Anna to control her power the way Elsa learned to in Frozen. Much is made of Elsa’s obvious Power Incontinence, but if love is Anna’s power, then it’s clear she has Power Incontinence of her own, which first appears when she falls in love with the first pretty face she sees. Anna’s devotion to protecting Elsa in Frozen II appears as a fierce and rather sweet loyalty, but it’s also Power Incontinence of a sort – she has obvious abandonment issues, becomes clingy rather than protective, and interprets every word of Kristoff’s bumbling proposal attempts as a breakup instead. She pleads desperately with Elsa not to be left behind as Elsa goes to Ahtohallan, and it’s no accident that, before Olaf flurries away, he tells Anna that she’s going to have to “do this next part on your own.”
Anna tells Elsa that her (that is, Elsa’s) powers are a gift; a reward for their mother’s act of love in saving “her enemy” (Agnarr.) But is she right? Characters can interpret events incorrectly: Elsa says she awoke the spirits, but they were already awake, which we know because the Northuldrans don’t want to go to the north part of their land, where the earth giants roam. They’re already awake; Elsa merely answered a call, and the spirits set the events of the film in motion thereafter.
If Anna misunderstands, then why does Elsa have ice powers? The answer (naturally) is in Ahtohallan, though Agnarr and Iduna probably wouldn’t have learned it even if they’d made it there. Once we get to see Ahtohallan for ourselves, it’s clear that Anna (or anyone without Elsa’s powers) could never have navigated the place. Elsa has to get past several obstacles before she can see any memories: an ice slide with a huge chasm at the end, giant fallen blocks of ice. This is even assuming Anna wouldn’t have frozen to death; we don’t know just how cold Ahtohallan is, but it’s possible only someone with Elsa’s tolerance of cold would’ve even been able to go inside. Regardless, Elsa’s ice powers are a requirement to see the memories Ahtohallan contains. It’s the only way across the chasm and the only way to lift the massive blocks of ice.
Therefore, Elsa’s ice powers aren’t a reward from the spirits. They’re a necessity – not just to see the memories of Ahtohallan, but ultimately to lift the mist and to restore peace between Arendelle and Northuldra. Only someone who can see the memory of King Runeard could find the truth about the dam and Runeard’s intentions.
But then, why doesn’t Anna also have ice powers? If she did, she would go to Ahtohallan too. Both sisters would learn the truth, and then return to break the dam....right? But it wouldn’t work that way. Iduna sings: “When all is lost, then all is found.” Elsa only learned a hint of the truth about Runeard from the first memories she sees. To find the whole truth, Elsa had to “dive down deep” into the very bottom layer of Ahtohallan – where she froze to death. If Anna could go to Ahtohallan, she would’ve accompanied Elsa to the doom of them both – or else prevented them both from learning the truth. And finally, it takes an almost superhuman act of love on Anna’s part to realize that breaking the dam and putting the kingdom at risk is the right path. (Fortunately, the spirits also pushed all the people out of Arendelle, so that Anna could be secure in knowing she’s not putting actual lives in danger.) They had to be apart, so that one could find the truth and the other could act on it.
So, Elsa hits the nail on the head when she tells Anna, “A bridge has two sides, and Mother had two daughters,” implying that Elsa and Anna, together, are the fifth spirit. This, of course, is why they had to be holding hands to get through the mist. The spirits could pass through the mist at will, but Elsa is not a spirit by herself, and neither is Anna. As the fifth spirit, together, they could do it. And the two movies’ mirror image returns, when, at the end of each, one sister finds the other alive when they thought they were dead. Anna simply tells Elsa, “I love you” at the end of Frozen, which is the key to Elsa learning to control her ice powers. Elsa tells Anna, “We did this together,” at the end of Frozen II, which is the key to Anna learning to control her love – that is, Anna learns that working together doesn’t have to mean literally right next to each other at all times.
This, then, is the true origin of Elsa’s powers. They’re not just a gift for Elsa to play with. They’re needed in order to restore peace – and so are Anna’s. Elsa can be seen as the combination of air and water; Anna, as fire and earth. They have to work together, and as foils for one another to help each other grow and control those powers. Elsa’s ice appears to be the more powerful to an audience of people (and characters) unused to seeing it; after all, she can literally walk on water, among many other things. But love can thaw a frozen heart; and Anna does not say, after unveiling the statue of her parents, “Our lands and people, now connected by ice.” Their powers are equal. Ultimately, Elsa and Anna’s powers exist as the elemental spirits’ way of bringing about a lasting peace.
