Their relationship — the love they have for each other, and the lengths they're willing to go to save the other — is the beating heart of Frozen. Without it, the story wouldn't have worked as well, nor would it have been as heartfelt and personal. Being sisters gave Anna and Elsa something to fight for: Each other.

In the lore of Disney's Frozen, Anna and Elsa share a deep, profound familial love as sisters, which is the emotional core of the franchise. The original film famously subverted the "True Love's Kiss" trope by revealing that the "act of true love" required to thaw a frozen heart was Anna’s self-sacrificial protection of her sister, rather than a romantic gesture from a prince. This bond is a central theme of "Agapé" love—unconditional, sibling devotion. While fans have long speculated about the characters' romantic orientations (particularly the "Give Elsa a Girlfriend" campaign), Disney has maintained that the sisters' relationship is purely platonic and familial. In Frozen 2, this bond is further solidified as they realize they are two halves of a whole, with Elsa serving as the "Fifth Spirit" and Anna as the Queen of Arendelle. Their love for each other is presented as the most powerful force in their world, but it is explicitly the love between siblings who have overcome isolation and trauma together.