This is a collection of story ideas/headcanons I haven't seen posted yet that I hope someone will take up. These ideas include lots of background info about the world of Frozen, as well as pairing ideas for Kristanna, Elsanna (mostly), Kristelsanna three-ways, and unconsummated pairing ideas.

This idea was dubbed "the ultimate headcanon" by some members of the Elsanna tumblr community, so it's first on the list...

Elsa's parents took their one darkest secret to the grave with them.

They, themselves, are brother and sister, their love so strong and true that it conquered every obstacle and allowed them to hide their secret from the world – but not from the heavens. As punishment for their un-natural union, their firstborn (Elsa) was cursed, leading to years of suffering by their entire family.

(Elsa's parents could not have pulled off their marriage without outside help. They went to the trolls, begging Pabbie to make their feelings go away. But he could not, because "the heart is not so easily changed," and instead helped them to get married - by faking the sister's death and allowing her to pose as a wealthy foreign princess, whom the brother would then "choose" as his bride.)

But it turns out there was a perfectly natural cause after all: Nature herself sometimes makes mistakes. Due to a fluke germ-line mutation in Elsa's grandmother, both of Elsa's parents were biologically insensitive to the Westermarck effect, and as a result, experienced non-normative "genetic sexual attraction" wherein their close sibling bond and shared traits (from genetic similarity) only increased their unconscious desire for each other as perfect mates. Elsa and Anna inherit this mutation (since both their parents have it), and as a result, are similarly irresistibly drawn to each other – though they never know the true reason, as modern biology doesn't exist in their time.

This idea was my second most popular submission...

Anna never got the "birds and bees" talk, and actually doesn't know what sex is throughout the events of the movie

Anna was only 15 when her parents died, and typical age of puberty is much higher in their time than in the present day. So mom never got to give Anna "the talk" (about the duty of a princess upon marriage). This means Anna literally does not know that by asking to marry Hans she's also asking to have sex with him (and she wants Elsa to give her blessing). She doesn't even know what sex is. To her, it's all just something that she'll find out after she gets married (which is the ideal, but is just some nebulous concept in her head that she's been taught is a good thing).

Elsa, however, did get "the talk" (being 18 when their parents died) and she DOES know what it means for Anna to get married. She also knows that Anna probably doesn't know! (That's partly why she wants to talk to Anna in private – to ascertain whether Anna did or didn't get "the talk")

After the movie, Kristoff is aghast to find out that Anna doesn't know what sex is. He doesn't want to give her the talk, both because it's not right for him to take advantage of her and because it's really best if she gets the talk from a woman, preferably a family member – meaning her sister.

This means that *Anna has to ask Elsa for the "sex talk" after the events of the movie*

But, having had "the talk" herself, Elsa is also painfully aware of the true nature of her feelings for Anna. And that means Elsa really, REALLY doesn't want to be the one talking about this with Anna!

Elsa knows that she would have denied Anna's request to get married *regardless* of who Anna brings as a suitor. And she hates herself for it, and she fears being discovered (which is another source of the fear she felt when Anna came for her on North Mountain – her fear of accidentally freezing Anna, which is mostly because she has that underlying fear of her romantic feelings in the first place that is keeping her from controlling her powers).

At the end of the film, Elsa is so relieved that Anna came back to life that the pure joy allows her to thaw everything. However, it won't be long before Anna starts getting serious with Kristoff and Elsa's jealousy is re-triggered.

So what does Elsa do when Anna asks her about sex?

Well, that's anyone's guess.

Hope these ideas have given you some inspiration for your own fics! There are plenty more, check out the chapter menu.