This is my first fanfiction, so constructive criticism is very much appreciated!
Prologue
About ten years ago, before the destruction of Jotunheim, Thor and his five closest friends (one of which being his brother) journeyed to the realm of the frost giants against strict orders from Odin. Thor's fury against the Jotuns had blinded him from the dangers and caused him to lead his friends into a battle they could not win. The six warriors fought bravely, striking down several giants with ease, but they had not taken into account the small figure who seemed to simply melt out of the ice. At first, the mysterious hooded person simply watched the battle, and the Asgardians paid them little attention. It was only when the fur cloak shifted to reveal a shining, silver-shafted spear did they worry. The figure, though smaller in size, very nearly outranked Thor and his friends in skill. It fought with an agility and grace unknown to any of the warriors, not to mention its weapon. The spearhead was crafted of some nameless crystal that glowed with a faint blue light. Though the figure was clearly fighting the Asgardians, many of the frost giants lashed out at it. One of the great blue monsters caught it by the arm, and a thin layer of ice quickly spread over the animal hide protecting it. The unknown warrior struggled in vain, the ice growing thicker. In their frantic attempts to escape, the fur lined hood of their cloak fell, revealing long snow white hair and the face of a young woman, no older than fourteen.
The girl's frightened gaze darted from one Asgardian to the next. Her motions began to slow, her efforts becoming half-hearted, and her spear clattering against the frost covered ground as the cold began to reach her. Out of the corner of his eye, Thor caught sight of this. He swung his arm back and with a mighty throw, hurled the hammer into the chest of the unsuspecting frost giant. The girl tumbled backwards, falling hard against the ice at the sudden absence of the Jotun. She cringed and put an arm over her face at the formidable sight of Thor looking down at her. Moments later, however, she heard a quiet thud and felt a hand resting on her forearm. She let her hand be gently pulled away and looked up at Thor in subdued bewilderment.
"Are you hurt?" his regal voice was surprisingly clear, despite the sounds of battle raging behind him. The girl shook her head, though her expression was guarded. Thor pulled her to her feet, picking up Mjölnir as he did so. Loki, having defeated his immediate adversaries, made his way toward them. He picked up the silver spear and smirked. The girl scowled and attempted to lunge at the smug god. Her furious attempt, however, was halted by Thor's grip on her arm. She continued to glare at them, and it was quite evident that she was struggling with all her might to get away.
Just as Loki opened his mouth to speak, a burst of multicolored light connected with the frozen ground behind them. The bifrost. When the light cleared, Odin, King of Asgard sat proudly on the back of his eight-legged horse. In her captors' brief moment of surprise, the girl twisted her arm free and attempted to run. After traveling barely a meter, the ominous sensation of a blade pressed against her neck stopped her in her tracks.
"Ah, ah, ah. Not so fast," the unmistakeable whisper sent a chill down her spine. "You didn't really think you could get away that easy, did you?" Loki laughed, letting his dagger shift just enough to draw blood. The girl winced, biting her lip to keep from saying anything in response. "And anyway, you've got somewhere to be," he remarked, leading her towards the open bifrost. They stayed out of sight of the other Asgardians, though the girl did not quite understand how, as there was now utter chaos erupting across the battlefield. She closed her eyes tightly as they stepped into the blinding light.
In moments, Asgard lay before them, shining with all its glory. The girl blinked in the golden light reflected off the buildings. The prisoner, for she had by now realized that must be what she was, had little time for sightseeing as she was dragged swiftly into the palace. Once inside, Loki led her down endless corridors, twisting and turning until she very nearly forgot which way was up. Eventually, they stopped just outside the dungeon, out of earshot of the guards standing by the doors.
"You want to know who I am," the girl said, speaking for the first time. Her voice was cold and smooth, something in it hinting at dangerous secrets. She also had a peculiar accent, one that is easily recognized, but one couldn't say where it's from.
"Among other things," Loki agreed with a smirk. He pressed the flat edge of the knife against her shoulder.
"And please, tell me how you expect to convince me to explain anything. If you haven't already noticed, I don't quite fear for my life," she kept her voice low, watching either end of the hallway.
"Well, I'm not blind. Let me make you a deal," the Asgardian began. "You can stay here and rot in a cell for the rest of your natural life. Or-" He stopped abruptly, seeing something change in the girl's steel blue eyes.
"The rest of my natural life?" Inexplicably, she laughed, a laugh with madness tearing at its edges and ice frozen in its core. The god of mischief, it seems, had found and ally.