Disclaimer: I recommend you read this at least once so you can't say I didn't warn you.
I do not know the Marvel comic books save for what Wikipedia might tell me. Therefore, the characters that appeared in the movies are going to be based more off their movie versions. I'm mixing real Norse mythology in as well, but with my own twist on it, so everything is going to be a little off what 'real' canon is, but not enough that I feel it's a real AU. Considering that Marvel AU's their own canon all the time, though...well....
There are also homosexual dealings. Keep in mind they're not actually related to each other if brotherly love taken to the physical level squiks you out. Also keep in mind that Norse Loki is Omisexual and will boink anything with a pulse, no matter what gender he or it happens to be.
Loki stood before his polished mirror and slowly smiled, stretching his face and then letting his expression broaden naturally when the motion didn't cause him pain. He was finally healed.
For two years he'd lain beneath the ground of Midgard, a magical, ever dripping venomous snake poised above his head. At his side with a large bowl had knelt Sigyn, his wife, prepared to catch the venom. But he had tricked Sigyn into that marriage years before, having killed her betrothed, Theoric and disguising himself as him for the marriage ceremony to reveal his true form only after the vows. For that she had made sure to get vengeance on him.
Though she had loyally held the bowl above the venom until it was full, whenever she had to empty it she had made certain that some of it would spill upon his body. Those two years had left him scarred and pockmarked not only on his face but on his body as well. Her betrayal of him was too great to ignore, but rather than punishing her for it, he had rewarded her. Once he had been freed of his imprisonment, he had traveled with cloak and mask to the graveyard outside Valhalla to locate Theoric's grave and use the darkest of necromantic magics to return him to life. He'd hid Theoric away while the reborn Asgardian was regaining his strength so that he could return to the Golden Halls to formally divorce his wife.
He scowled now, thinking of her, and turned away from the mirror. How shocked she had seemed and how bitterly she had wept, acting every bit the heartbroken woman when he had announced that he would no longer have her. That was, until Theoric arrived, at which point she had become subdued, softly thanking Loki for returning her real betrothed to her.
He made a cut off motion with his arm in silent protest against his own thoughts, once green eyes pale blue with his emotions. Sigyn had what she'd wanted all along and was of no more matter to him. Anger still boiled in his heart thanks to her however.
When he had been allowed back into Asgard, he had been neither offered nor taken to the healers, leaving him to walk about cloaked and masked or to isolate himself in his room to hide his maimed features from the other Asgardians until he could heal his injuries himself. It was Sigyn's doing that he so badly maimed, and it was Sigyn again that had no doubt prevented him from being given medical aid. Rather, he had been left to weave the healing spells himself, an agonizing process after his magic having been locked away for those two years. For six months he had endured in self-exile, accepting no visitors and gaining few knocking upon his door regardless save for Thor and his adoptive mother, Frigga.
But now his face was unmarred once more and his body held only shallow pocked scars. He could finally once more walk among the other Asgardians without being an object to be pitied. With that thought in mind, Loki set about dressing in his finery. He knew to whom he had to first present himself, and he wished to start with a good impression.
Odin looked down at the green and gold clad figure kneeling before him and he smiled faintly. "Loki." He greeted his adopted son in a soft voice rich with weary affection for the troublemaker. "We have been long wondering when we would see you walking the halls once more."
"It has been a long and painful recovery, Father." Loki responded, lifting his head but remaining kneeled, fist held still over his heart. "But I am here now." He hesitated briefly, and then moved to stand. "A guard said you wished to speak to me when I could....I apologize for making you wait Father, but I....was still too scarred to be seen."
A flicker of pain crossed Odin's features and he shifted on the throne uncomfortably before he moved to stand. He set his helmet and staff aside, and then descended the throne. "Walk with me."
Loki inclined his head to the Allfather and moved to fall into step beside him. They walked in silence for several moments before Odin gave a soft exhalation.
"You could have sought out the healers, Loki." His tone, which could be as booming as Thor's thunder when he was angered was no more than a breeze whisper. "There was no need to suffer all these months."
Anger flickered in Loki's eyes, their sky blue hue turning pale. "I was neither offered nor taken to the healers after my return." He responded, his own tone tight with forced control.
"There was fear, Loki. You held great rage within you when you returned, the guards were afraid to speak lest that anger turn upon them. Even Sigyn feared you then."
"I am always feared." Loki turned his face away and clasped his hands together to resist the urge to punch the wall, though frost was forming behind his steps as they walked. "Because of what I am."
"You are an unknown, Loki." Odin spoke gently. "The son of an Asgardian and a Frost Giant. There has never been hearing of such a thing before. But it is your ambitions they fear even above your blood."
Loki grit his teeth, the frost beginning to thicken into ice in his wake and the hallway becoming noticeably cold. "When Thor and I were children, you said we both had potential to be your heir, yet there was never any question whom would ascend the throne. If I have had such ambitions, then it is because of the possibilities you dangled before me."
Odin sighed heavily and ran his hand over his face briefly. "The people favored your brother, Loki. I could not do anything about that." He glanced back at the ice and sighed again. "It isn't like you to lose control this way. Even in your darkest tempers, you haven't been like this before...."
"My time at the mercy of a venomous snake and a traitorous woman seem to have changed me." But Loki drew in the cold all the same, allowing the temperature around them to return to normal, though his eyes remained an almost gray hue.
Odin sighed again and took Loki's shoulders in his hands, halting their forward motion and turning the younger to face him. "Loki. Though you are not my son by blood, do not doubt my love for you. You are my son as much as Thor is. There can only be one King of Asgard, but that does not mean you do not have a place in the throne room. You are clever and you have wisdom. Thor could use you at his side, and for that matter, so could I."
Loki looked his adoptive father in the one eye he had left and then finally, he inclined his head, the anger leaking from his eyes and allowing them to return to their former sky blue. "You're right, Father. One cannot command the love of the people." Yet.
Odin patted Loki's shoulders and smiled to him. "Go see your brother." He advised. "He has been worried for you."
"I will." Loki promised. "But Father. What did you want to see me about?"
"Ah yes. I have need of your diplomacy." Odin motioned to the necklace collar Loki had been forced to wear since just before his imprisonment beneath Midgard's crust. "It is not an urgent matter however, Loki. Go see your brother first and then we may speak of it."
"....Yes, Father." Loki stepped back and bowed to Odin, then turned to go. Once away from the Allfather's gaze, he touched the necklace collar and frowned. The decorative contrivance kept him from using the dark paths between worlds and realms, and yet, after only a mere two years and six months they were going to remove it again, however temporarily? This had to be big, and more important than Odin was saying. Loki smiled to himself. Yes, he was important to Asgard, and even if he truly couldn't be King--which was still up for debate as far as he was concerned--he could prove himself invaluable in other ways.
But first things first. He did want to see Thor.
The practice hammers flew true to the targets and then were called back to the hands of Odin's eldest. Again and again Thor threw the two hammers, smaller than Mjölnir but still capable of inflicting a great amount of damage. Calling them back to his hands once again however, he found he was abruptly missing one and straightened up in puzzlement.
"Do you ever get tired?"
Thor turned to see Loki approaching, holding his missing throwing hammer and his confused expression bloomed into a smile. "Loki!" He dropped the other hammer on the ground and hurried over to him, though his smile then transformed once again into concern. "Are you alright?" He brought his hands up as if to cup Loki's face, but then hesitated. "You kept yourself in your room for so long. I feared...."
"Fear no longer, Thor." Loki smiled and dropped the hammer he was holding off to the side. "I am well."
"Mm." Thor's hands closed on Loki's face and he pulled him close so that their foreheads touched. "It is good to finally have you back, brother."
"....Is it?" Loki asked. "I seem to recall a great deal of animosity."
"That was on your part, brother, not mine." Thor's hand moved to cup the back of the younger's head, holding him close as if he could somehow meld their thoughts together from the contact. "You are home now, and you are well. My heart is filled with joy."
Loki chuckled softly and closed his eyes. "Even though I have done so many things against you? Against Asgard?"
Thor was quiet for a time, and then he let go of Loki and took a step back. When Loki opened his eyes, he found the other looking at him sadly.
"I am sorry, brother." Thor spoke, his tone pained. "Whatever I did to make you feel as if you walked in my shadow. Truly, I am sorry. I never intended to make you feel as if you were less than I."
Loki took in a deep breath, let it out slowly and smiled. "I know." He said, and he did. Thor was as honest as Loki was the opposite. The great blond brute seemed unable to give voice to a lie.
"Well," Thor continued, deeming that all was well now and beginning to smile again. "This is good, is it not? All together on Asgard as it should be. A family again."
Loki sighed softly and shook his head. "It's just that easy for you. Forgiven and forgotten....I almost envy such innocence."
"Tis not innocence, brother." Thor corrected. "Tis faith. In the end, you are always my brother."
"I am not your brother!" Loki abruptly snapped. He turned away, summoning the dropped practice hammer to his hand and spinning back to throw it at the target, though he did not have Thor's strength and it fell well short of the mark. He followed up with his throwing knives, which did strike true, fixing deep. Loki finished it off with a blast of magic that blew the otherwise durable target apart and then stood there, panting while Thor just watched him sadly. After a few moments Loki straightened up and looked at the other.
"I am not your brother." He repeated, softer. "You know what I am, you know that I am not blood. I am not truly welcome here. Even before....ever in your shadow. Ever walking in your wake. Outcast and unwanted."
"You are not unwanted." Thor strode the short distance to him and put a hand on Loki's shoulder. "I love you and Father loves you. You are my brother and you are his son. It does not matter if you are blood or not, you are still a Prince of Asgard."
"Always a Prince, but never a King." Loki intoned bitterly. He pushed Thor's hand off his shoulder and walked over to the shattered target to collect his throwing knives.
Thor gave a frustrated snort and called the throwing hammers to his hands so that he could return them to the weapon rack, then he waited for Loki to walk back over before restarting the conversation.
"I understand, brother." Thor said sadly, watching as the other began to pace around the training area. "You believe you are less than I because of our different skills, because those of Asgard always looked to me before you. I remember that time not so long ago when I had let all of that go to my head, when I'd put us all in danger taking us to Jötunheim. If only I'd been wiser then...."
"If only...?" Loki ceased pacing to face the older and spread out his arms, a bitter laugh escaping. "You lament because I may not have discovered my heritage then, not because of true regret. You would have killed them all, Thor Odinson. Do not forget that."
"They had broken into Asgard and almost succeeded in taking the Casket!" Thor shook his head. "But I was still rash, overconfident. It almost cost us all dearly, not just you....but you're right, regrets matter little. They got it regardless and we have lost the means of chasing them down further."
Loki rolled his eyes and put a hand to his face briefly. "You are so blind." He muttered in disbelief. He looked back at Thor and shook his head. "They never got the Casket, Thor. I have it. I have always had it."
Thor looked at him in shocked surprise. "You? But what need have you of it?"
Loki sighed in exasperation. "I see why you are not yet King quite clearly. You are so very very naive." He turned away, shaking his head, but then he suddenly turned back again with gray eyes and pointed at the other, frost forming on the ground around his feet.
"Didn't you ever figure out who let them in, Thor Odinson? Don't you realize the only one who could have had the power to sneak Frost Giants into Asgard right under Heimdall's nose could only be me?!"
Now it was Thor's turn to sigh. "You think me blind, brother, for my forgiveness of your faults and crimes. Yes, I know you let in the Frost Giants, though I did not know that you held their Casket." He stepped toward the younger. "You fail to see that I do not care of these things. You are my brother, blood or not. My love for you will not waver, Loki, no matter how much you strive to make it so, though I cannot understand why you go to such efforts."
Finally Loki's expression crumbled and he lowered his head. When Thor reached out to embrace him, he didn't stop him, though he didn't return the affection and only rested his head on Thor's shoulder, eyes slowly closing and the frost melting away again. "Why....?" He whispered. "Why do you still care...?"
"Because you are my brother." Thor responded, clearly believing this to be ample explanation.
Loki chuckled bitterly and shook his head slightly. "......As you wish." He brought up his arms to hug Thor back and they stood there for several moments before Thor let go and Loki was able to step back.
Loki smiled slightly to Thor and patted his shoulder. "I will see you later, Thor. It has been a long time since I have been able to walk about freely and I wish to reacquaint myself with Asgard."
"Of course, Loki. Will you be joining us for the evening meal?"
"I suspect I will." Loki turned to go, inwardly sighing. How could someone that trusting possibly be a good King for Asgard? The Allfather surely had to be taking leave of his wits.
It was almost pitifully easy to get past the guards posted before the Vault. An illusion of hiding, a quick cast of a sleep spell and they were out. Loki walked slowly down the steps and past all the relics and weapons held within. He paused briefly, then straightened up and tilted his head.
"You were following me?" He remarked to the one standing in the doorway of the Vault.
"It's not here." Sif said, beginning to descend the steps to approach him, her two-headed spear held close to her side. When Loki turned, he could see she was fully armed for battle and he arched a brow at her.
"It's not here?" He repeated.
"The Tesseract. It is held in another's keeping, out of your reach."
"Still in Skaði's possession, then." Loki summoned the Casket of Ancient Winters and watched with inward glee when Sif stiffened, he turned away however to walk the rest of the way to the end of the hall and place it upon the pedestal on which it had once rested several years before. He was just lifting his hands off the handles on the sides when he heard Sif sprint the distance between them. Moments later, he found one end of her spear held to the side of his throat.
"So it was you who stole it." Sif snarled.
"Held in keeping." Loki responded calmly. "Now returned. You have no reason to be so irate."
The edge of the spear touched his skin and Loki couldn't help but flinch slightly at the sharpness of it. "What else do you 'hold in keeping', Loki?" Sif's tone was definitely hostile. "What more deceptions do you have in mind to threaten Asgard?"
Loki's brows furrowed. ".....Have a care, Sif. I paid my penance, as you and all of Asgard well know. I have little interest in having what I have regained taken from me again."
"Two years is a paltry time for crimes such as yours. Your sentence was not fully served out, Jötun." The spear's sharp edge drew a thin line of blood from Loki's throat. "Speak! What more plots?"
"Even if I had such," Loki's form dissipated from in front of Sif to reform behind and he grabbed her spear with one hand while he locked the other arm around her waist so she wouldn't be able to very easily move. "do you think I would speak of them to you?"
She struggled against him, however ineffectual it was, for though Loki was not as strong as Thor, he was still stronger than her. "Damn you!"
"I understand your dislike of me." He whispered by her ear. "For having so hurt Thor, you condemn me harshly. But I have paid my dues, Sif. Can you not find it in your heart to forgive my past transgressions?"
"As you wish." Loki let go of her waist and pushed her forward, keeping his other hand on her spear. She too kept her grip on it, but as she spun around to face him, her free hand happened to hit the center of the Casket, which gave a flash and instantly coated her hand and part of her lower arm with frost.
Sif screamed in agony and jerked away, letting go of her spear to grab her arm with the other hand and then release it again quickly when the frost tried to coat her other hand. She backed away from Loki and the Casket, holding her frostburned arm as close to her body as she dared.
"Ooh." Loki tsked. "That looks painful."
She glared balefully at him. "So, you take pleasure in my pain. That suits."
"So says the woman who was threatening me with a spear." He held the hand not still holding her weapon out to her. "Give me your arm."
"I shall do no such thing!"
"You can continue to suffer," Loki still held his hand out. "or you can allow me to help you."
Sif glared at him for several moments more before she stepped forward again and thrust her injured arm at him all defiantly. He closed his hand on her lower arm and as she watched, the frost crawled off of her and onto Loki, showing his Frost Giant heritage as his hand turned blue and ridged as he absorbed the cold into himself. Letting go of her arm when he was done, Sif retreated from him and watched as his color slowly returned to normal.
"You really are a Frost Giant." She hissed softly.
"And yet still a Prince of Asgard." Loki flashed his teeth, and then tossed her spear to her. "So watch how you speak to me, lest I become offended."
Sif caught the spear awkwardly, her formerly frostburned arm still hurting a fair bit and eyed Loki warily. "It seems as if the acid viper did no lasting damage to you. A pity."
"Oh, thy tongue is sharp, Sif." Loki bared his teeth at her again in a feral smile. "You want to see what the vile snake did to my countenance?" He passed a hand over his face. "Behold then, if you can bear the sight."
Sif gasped at the illusion Loki now wore. Flesh burned away, exposing muscle and bone along his cheek and forehead on both sides of his face. Part of his nose and right eye were gone and she could see a couple of teeth where the acid had leaked under the muzzle he'd worn those two long years. His throat too had been exposed, blood leaking in small spurts with every beat of his heart and his breath whistling with every exhale.
But Loki wasn't finished yet. He undid his tunic and opened it to show Sif the rest of the damage. Ribcage exposed along his right side, air hissing out from a partially collapsed lung, half-dissolved muscles straining and quivering to expand his ribcage with every painful breath. The acid burns continued even lower, pocking into his hip and hinting at even more damage below his beltline.
Sif in all horror, couldn't bring herself to look away and Loki gave her a good long look before he did up his tunic again and dispelled the illusion so that the facial damage only slowly vanished.
"Six months it took me, dear Sif." He told her, dead eye rolling in her direction as it became sighted once more. "But it was never meant to kill or maim me permanently or my own healing magic, such as it is, would not have worked. Six months it took me to heal, but two years it took to do that and yet you claim my penance is not yet through." His lip curled back in a snarl. "Thy art a sadistic one, Sif."
Sif swallowed hard, obviously shaken. "......Why did you come into the Vault, Loki?"
"To return the Casket to its place and nothing more." Loki's smile this time was almost mockingly kind. "Shall I see you at the evening meal, sister through marriage?"
".....Not as like." Sif attempted to regain her composure. "Your first meal outside your self-exile should be with family alone." She pointed her spear at the door. "If you are done in here Loki, then I would advise you to leave and make yourself ready for your appearance at the Allfather's table."
Loki chuckled. "I'm not in such a rush as that. Time yet to dally about, if I so chose." But Loki turned to leave the Vault without protest. He'd managed to shake up Thor's beloved, and that pleased him quite a fair bit. Like the Warriors Three, she had never much cared for him and now it seemed that wary dislike had bloomed into full out hatred, or something akin to. Well, two could play at that game and he had learned much crueler tricks during his exile in the company of the Other and his Chitauri. If she would not respect him, she would at least learn to curb her tongue in his presence.
He left the Vault, waving his hand back at the guards to undo the sleep spell so they would gradually begin to waken and finding his mood at last beginning to truly lift. He was home, and he suspected that in spite of the court knowing of his true birth, nothing much was going to change. It had been two years and six months since they'd last all seen him, after all.