The Asgardian sun was hot and bright in the midsummer afternoon, causing sweat to drip into Sif's eyes as she ran along the trail near the river and the image of Thor far ahead of her blurred, the prince heading with his friends to the training grounds, not turning back to the sound of Sif's voice.

"Wait for me!" the young girl called after her older companion. She fumbled with the sword that was nearly as long as she was tall, and swore as the heavy shield Thor let her borrow from the armory fell from her small shoulder onto the ground.

Loki snorted from his perch in a nearby tree, unseen until then and startling his classmate below. Sif glared up at the younger prince but he did not meet her gaze, one leg slowly swinging from the high branch as he casually read from his shaded hiding spot.

"Is there something you wanted to say, Loki?"

"If you haven't noticed, all the Valkyrie are dead," Loki licked his thumb and slowly turned the page of his spell book. "A girl can't be a warrior."

Sif threw her sword to the ground. "Says who?"

Loki shrugged, his eyes still on the page before him. "Everyone. You should hear what people say behind your back, how embarrassing it is to see you rolling around in the dirt. A real girl isn't meant to act so undignified."

Sif's nostrils flared in anger and a burning sensation scorched her guts.

"Oh yeah? Well, magic is for girls. A boy can't be a witch!"

Loki snapped his book shut and finally turned his gaze upon her. "Take that back!"

"Never! You should hear what people say about you, about how pathetic it is for a prince to waste his time on magic and how someone so weak could never lead Asgard."

Loki dropped down from the tree, his shoulders raised in anger. Sif balled her fists and returned his angry gaze.

"I'll show you!" the young boy shouted, his hands turning a glowing green. "I'm going to be the best sorcerer there ever was and I'll curse you with every hex in the universe!" A ball of green energy slammed into Sif's chest, sending her to the ground. Rage propelled her back to her feet immediately.

"I'd like to see you try!" Sif charged at the boy, her fist connecting squarely with his jaw. Soon the children were tumbling on the ground, trading blows and insults. Sif was aware of someone grabbing her by the back of her tunic and hauling her entire body off the ground and away from Loki.

"Enough, Sif! Enough!" Thor's voice boomed. He dropped Sif to her feet and turned towards his younger brother, his body blocking Sif from re-engaging the tussle. "Peace, Loki!"

Loki lifted himself to his feet, his hair falling into his and his nose running with bright red blood, but Sif was surprised, and enraged to see him grinning at her. Did he mock her strength?

"This isn't over." She growled around Thor's arm holding her back. "I'll show you, Loki. I'm going to be the best warrior in the entire cosmos and one day I'll have your head on a spear!"

Thor bellowed in outrage at the threat, but Loki bowed towards her, still grinning, but his voice was dangerously low, "I'd like to see you try."

Sif returned his grin, accepting his challenge as he walked away from her, retrieving his spellbook and disappearing back into the palace.

And so it progressed; no matter how she was scolded by her mother, everyone insisting that Sif could not speak to a prince in such a manner, no how often Loki was berated in his etiquette classes, the rivalry only seemed to grow as the years passed. Each child keeping their promises to grow their skills as they grew into teens and beyond.

Sif's taunts of "You think you're so smart, I bet you can't get every question right" only provoked Loki to study obsessively, the prize of seeing Sif's face when he held up his perfectly scored test and stuck his tongue out at her.

It was Loki's disdainful shrug and question "What's so impressive about a single blade?" while observing her in the training yard that led Sif to compulsively develop her double blade; enjoying Loki's begrudging approval of the weapon.

Each day they challenged and goaded each other to run faster, study harder, climb higher, be better.

Now that they were on the cusp of young adulthood, the latest challenge had been made by Sif, betting that Loki did not have the skill to make his single mirage illusion multiply into many bodies. Sif had found herself noticing his body as their limbs had grown longer, age sharpening cheeks and filling out their training leather in new ways. She found herself surrounded by five of those bodies as they surrounded her in the training yard. Sif felt a thrill run through her as each copy grinned and advanced towards. She grinned too, for it certainly was an impressive work of sorcery, the likes of which she had never seen before. It was only the sound of a foot fall that gave away the true Loki, and she soon had him pinned under her. She ignored the racing of her heart that was not solely due to exertion when his hands rested lazily on her hips.

"Well met, my lady," Loki presented his neck to her with a satisfied smile, not making to move from underneath the weight of her. The sight made a heat pool in her stomach and she shivered from her perch straddling his hips. The shock of her response made her jump up, making her excuses to exit the training yards.

What just happened? She hated Loki, did she not? Why would her body betray her so? She questioned herself as she fled, seeking solitude in the only quiet place she could think of. This was a mistake of course, as she was not alone long before Loki, freshly bathed from the yard entered the library and sauntered towards the spellbooks.

Before she could stop to think, Sif found herself following him down a deserted wing and into a dim row of books. She shoved him hard in the back, causing the large book in his hand to fall to the floor. He turned slowly to face her, looking unsurprised at her attack.

"Hello, Sif."

"Do you enjoy provoking me?" She demanded, stepping closer to crowd him back into the shelf. "Always vexing and nettling me."

"I would classify it as bettering you," Loki grinned, making Sif's guts churn with annoyance and something else. "And I do believe you enjoy it as well as I, Lady. Always aggravating and confronting met. Am I wrong?"

He looked down at her through dark lashes, and the truth of his words was suddenly undeniable to Sif.

"Perhaps I do find it pleasing, My Lord. But enough of this talk," she hissed and lifted herself onto her toes, to see into his eyes. She issued her next challenge, "I dare you to kiss me."

A heat flared behind his eyes at her provocation, making Sif's stomach drop in pleasure. With a sudden move, Loki prowled forward, taking ahold of Sif's hips and backing her into the bookshelf. Caught off-guard and pinned, Sif could not form a protest before Loki pressed his lips to hers. He kissed her with a burning intensity, meeting her lips with the same fire that fueled him to surpass each challenge she had ever thrown at him.

Sif gasped, trying not let it turn into a moan when he pulled away. Loki looked down at her, smug and expectant.

"Is that all you've got?" She questions and quirked an eyebrow at him, one hand finding its way around his neck. Loki grunted and then reached down to grab Sif's thighs, hauling her up onto a shelf and pushing his body forward until her legs were wrapped around his waist. Sif couldn't stop her moan when he kissed her again, his lips and tongue caressing and his hands tangling in her hair pulling her closer. Sif had never been kissed so thoroughly, so skillfully.

Her body thrummed when Loki pulled away again at long last. She was pleased to see him look as dizzy as she felt, his body swaying into her and his hair falling into his eyes. His low voice whispered against her lips made her shiver. "Is the Lady satisfied?"

Sif shook her head. "Not even close." Loki smiled.

"Then issue your next challenge, and I will be sure to accept."

"I dare you to find a better use for that tongue than to waste it on irritating words." Loki grinned, hooking his agile fingers under the band of her leggings.

"Then I counter with the same," he purred as he dropped to his knees, dragging her garment down. "I bet you cannot keep quiet and avoid the attention of the librarian." Sif laughed from her seat on the edge of the bookshelf and then gasped, bringing a hand to cover her mouth and biting into the meat of her palm as Loki began to comply with her demands.

Nothing is more satisfying, Sif mused before she lost the ability to hold onto a full thought, than the exhilaration of victory.