Author's note: Please see my profile for how I came to write this story!
The Dividing Moment
The frozen blizzard was standing still in the air, allowing Anna to glance back at Kristoff one last time. But she quickly turned around, for her mind was already made up. Elsa was her sister! She was in danger! She had to go to her! Anna felt the icy curse on her heart starting to burst out. Her limbs were becoming rigid and numb. She knew she was in imminent danger of freezing completely. But none of it mattered. The choice to protect Elsa wasn't really hers to make; her heart had made the choice for her a long time ago - perhaps when their parents died, or perhaps back in their childhood.
"Elsa!" shouted Anna as she threw herself between Hans' sword and her sister's prone body. In the same second that the sword touched her raised hand, her body began to freeze, starting from her heart outwards.
Who could know what differences these milliseconds would make? And how capricious is the human heart, which turns on such small moments?
Hans' sword sliced clean through the fingers of Anna's hand. It continued on to cut through her shoulder blade, the major arteries in the upper torso, part of her right lung, and finally hit her heart, where it was stopped by the ice that was now overtaking the rest of her body. The sword was now wedged in the middle of her torso.
"Anna? Anna! No!" shouted Elsa as she rose and turned around, noticing the commotion behind her. She looked, and saw Anna's ruined body - partly made of flesh and bone, partly ice. Anna stood unsteadily while her blood flowed down to her lower body and froze as it contacted the ice there.
With her last breath, even as she continued to bleed and freeze, Anna managed to say, "Elsa... he planned all this from the beginning... He was using me the whole..." In the midst of the preternatural quietness of the frozen blizzard, her last words were weak but distinct.
Elsa turned to look at Hans, with shock on her face. He started panicking - this wasn't what was supposed to happen at all! He tried to retrieve his sword from the Anna's frozen body, but it was stuck. Elsa's shocked expression mixed with sorrow, and she approached Anna's body to touch it. But Hans became ever more desperate and started flailing wildly as he tried to pull out his sword. At last, with a loud crack, the sword came loose, even as Anna's body - now entirely made of ice - broke completely in half and fell over. It hit the ground with another cracking sound as it fractured further, and lay in pieces between Hans and Elsa. Hans took several steps back. The silence roared in Elsa's ears, as it might when one falls into a black hole.
Elsa knit her brows in distress and anger. Her stare bored down into Hans. Her eyes flashed in her cold fury, as the tears she was about to shed for Anna became ice in her eyes. "Snow Queen Elsa" began Hans, as he adjusted the grip on his sword and raised it, his expression a chaotic mixture of fear, panic, and malice. "This can… This can only end one way! You are a curse upon your kin and your kingdom! The only way…" But he was cut off by Elsa's loud cry of wrath and despair.
As Elsa screamed she channeled all her powers and emotions into a piercing beam of cold, driven by all the winds of the frozen blizzard that had been standing still until this moment. She struck Hans through with it. He was no match for Elsa. His body froze and shattered instantly, but Elsa continued to scream and continued to channel her power to where he had stood, with the blizzard funneled through that spot in ever-increasing gale-force winds. She kept going and going - her blizzard's flurry obscured all of Arendelle in mere moments, but her growing storm continued to rage on and on, and Elsa kept pouring forth her full power. It is said that she did not stop until every molecule of water in Hans' body was part of a different snowflake. By then, her screams were taken up into the howling of the wind, and her body had started turning into ice - for her own heart had been frozen in the midst of her cataclysmic loss and release of her powers.
Now, Elsa the Snow Queen wanders the frozen northern lands, bringing her perpetual storm to wherever she goes. Her icy power continually flows forth from her uncontrollably. Her frozen heart and slowly freezing body doesn't bother her. The places she wonders upon are cursed to an eternal winter, since in her current state, all that she's ever frozen can never be thawed or melted. But she continues travelling. She searches for the only thing that may give her any comfort or closure - the remains of her sister Anna, which were blown away into the storm when she killed Hans. She believes that her powers would recognize the ice pieces that were once a part of Anna if she ever comes across them. It is a forlorn hope, but it is also her only hope, the only way she might find any measure of peace.
So Elsa walks upon the face of the earth, looking for her sister's frozen pieces, with her frozen tears still in her eyes - not knowing that alone among her terrible works, her sister's body was the only thing to ever thaw. For Anna alone had the true love in her heart that was capable of melting Elsa's ice. So Anna and her remains are gone now - thawed out and decayed and disappeared in the manner of all flesh - and forever separated from Elsa and her increasingly frozen heart, body, and soul.