Depersonalization
When they defeat the Chitauri and retrieve the Tesseract, Thor thinks it's finally over.
When he wraps his arms around his defeated, wicked brother, he thinks all will be well.
He will bring Loki home, to Asgard. Loki will serve whatever punishment Allfather deems suitable and he'll understand his mistakes and once again he'll be himself, Thor's little loyal brother standing by his side as he always had before.
There is no reason to doubt that. They have been companions and shield brothers and each other's sun and moon for millennia. This is but a mere inconvenience, just another quarrel that will eventually make their bond stronger.
Loki's fallen unconscious after the beating received from the great Hulk and stayed that way since then. His body's terribly light in Thor's hold and there's so little of him and his skin is glistening with sweat, pulled too tight over his cheekbones, eyes constantly twitching under his eyelids and mouth pulled in a frown but he's breathing and he's safe and he's there with Thor and it's all that matters.
Mother meets them at the Bifrost halfway to the palace. Tears are running down her beautiful face as she embraces the both of them, a sob of relief wrenching from her chest when she lays her eyes on her second son's unconscious face, cradles his head delicately to her breast like she used to when he was but a babe.
They take Loki straight to the healing chambers. The trial and punishment to follow can wait for when he's feeling better.
Thor then proceeds to the Throne Hall to return the Tesseract and report to Allfather.
He's not there when the healers strip Loki down and discover evidences of horrific torment he's been put through. He's not there to see the Chitauri brand etched permanently in the white skin of his brother's collarbone. Scars and burns and broken bones mended wrong. Remains of poison in his blood. White whip lashes all over his back, one on top of the other, crisscrossing in a tale telling of horror and suffering and despair.
There's traces of similar torture on his mind, Thor will be told later. Strange magic having bound his will, damaged his perception and perspective. Having made him passive, a tool in his tormentors' hands.
It's a relief and a heartbreak at the same time. Knowing Loki has done none of his crimes of his own will. Imagining what unbelievable anguish he's been put through.
Thor wants to scream and kill. Swing and smash and tear until there's none left of who did this to his little brother.
But they don't know. The wisps of strange magic left in Loki's mind lead to the uncharted depths of the Void. It's a guess from there. He thinks of Loki's fall. Of two years of absence, two years of grief until his unexpected arrival on Midgard.
Two years. Two years of Norns know what.
He wants to scream and kill and swing and smash and tear but he can only wait. Eir the main healer tells him and Allfather and Mother there's not much more than could be done. Loki needs to heal. He'll gain strength. His body and mind will purge themselves, given time.
And so, Thor waits.
Refuses to leave Loki's side for longer than five minutes. Watches by his bed, dozing in and out of a restless slumber. Frigga tries to coax him into going to bed for at least one full night of sleep but he doesn't want to hear of that.
It reminds him of when they were young and Loki would spend half of his days bound to bed, tormented by another one of his many sicknesses. Crying because he couldn't go outside and play with Thor. Tiny body shaking with fever and coughs and migraines and whatever would haunt him at the moment.
Thor doesn't budge. He's already failed his brother too many times. Doesn't want to do that ever again.
On the eighth day, Loki wakes.
It's just fluttering of his eyelids at first. Thor barely notices it happening. Thinks it's delusion at first but then Loki's eyes blink open slowly.
He waits, holding his breath. Waits for what's to come.
But Loki just stares at the ceiling above him, eyes glassy and strangely dull, their colour weathered. Thor can see the flickering lamps reflecting in them. His chest is rising in even, shallow intakes of air; face remains blank, not a trace of emotion visible.
And Loki's always been a master of hiding his feelings but this is different. Uneasiness stirs in Thor's stomach when his brother just lies there, indifferent, limp as a rag doll.
His eyes close slowly.
The blonde shuffles in place, unable to handle the tension.
'Brother,' he rasps, trying to make his voice quiet and even. It has always been a struggle for him. 'Brother, do you hear me?'
If Loki does, he gives no indication. One hand lying by his side curls slowly into a loose fist, bones long and bird-like. A quiet whine slips past his lips, face as passive as it has been until now. Like he's in pain but doesn't bother to act against it. Like he's used to it.
Thor loses it.
'Brother!' He says and makes the mistake of reaching to touch his shoulder.
Loki screams.
'You said he would be well. That the magic bounding his mind would be expelled by now. I do not understand!'
Thor is pacing back and forth across the infirmary, body buzzing with tension and anxiety. A low thunder rumbles in the distance.
There's only four of them. Him, Eir, Mother and Allfather. The four of them and Loki.
He's fallen into a fit of hysteria after Thor had tried to touch him. Fell out of the bed and crawled into the nearest corner twitching and screaming, shaking his head vehemently, tearing at his long tangled hair with claw-like hands. Thor stood back, paralyzed with fear, as the healers rushed in, alarmed by the screams.
He still hears them echoing inside his skull. Animalistic howls from within Loki's brittle chest, tearing at the joins of reality and turning everything around into a frenzy haze.
He didn't scream like he was scared or in pain. There was no fear, no misery. Loki screamed like he did it just for the sake of it.
Like he didn't remember how to do anything else.
They put him into a magic inducted sleep and called for their parents. That's how they ended up in this situation, Thor pacing furiously, Mother sitting by Loki's disheveled frame, gripping one of her hands between her two with a pained expression on his face. Odin standing behind her with a stoic, grim expression.
'It has been expelled, my Prince,' Eir tries in a break between Thor's infuriated cries. 'There is none left in his mind. The moment the Tesseract was returned-'
'Then why is he like this? Why does he act mad!' The Thunderer demands, advancing towards the healer. She doesn't do as much as flinch but her lips are pressed into a thin line and Thor only stops when Odin's voice booms through the room.
'Enough!'
His head snaps to the Allfather but his body listens on its' own and Thor finds himself frozen in place. His chest is heaving, hands balled into fists.
He doesn't understand.
Everything was supposed to be well now.
'My son is right, though,' the Allfather addresses the healer. 'You assured us that once Loki's mind was free of the invasive magic he would be returned to us. Yet from what I have been told, that is not the case.'
Eir wringles her hands, obviously worried.
'We do not know yet the exact reason for Prince Loki's outburst of panic. He hasn't been awake long enough to estimate that with precision.'
'But you have your assumptions, I believe,' Odin says. Composed, even. Always calm.
'I do indeed,' the woman admits reluctantly. 'It might simply be shock. Though if the marks on the Prince's body are any indication of the torture he's been put through...' She hesitates.
'Just say it!' Thor pleads. Father doesn't reprimand him this time, his single eyes boring into the healer.
'...he might have simply lost his mind.'
Frigga sobs violently, turning her face to hide it from the view. Odin's jaw clenches. Loki stays immobile, barely breathing. Thor doesn't know any of that.
The ground opens underneath his feet and he's the one falling this time.
Loki doesn't scream anymore. Though Thor almost wishes he would, for he interacts with the outside world no more.
They bring him to his old chambers, hoping that familiar surroundings will stir the missing part of him to life. They don't. Frigga attends to her younger son personally. Dresses him and feeds him and braids his hair and sings to him like she used to when he was little. She's in delusion and it can't be good for her but no one has the heart to stop her.
Loki's wounds heal. The scars remain.
He sits where he's left and walks when Frigga takes him to the gardens with her arm hooked under his and eats when they give him the spoon. Physically he's as healthy as he could be after being put through Hel.
He only makes sound during sleep. Whimpers and moans slipping past his lips bitten to blood and silent tears falling from his shut eyes and disappearing into his hairline. But he doesn't trash, does not turn or toss or jerk in his dreams. When Mother puts him in a certain position for sleep Loki remains like that all night, no matter what battle he's fighting.
Eir's worst assumptions are proven correct.
'I believe it's a defence mechanism he's come up with to shield himself from the torture. He's still there somewhere, deep inside, but I know of no way to reach him.'
Odin Allfather decides there will be no trial. It makes no sense to judge and punish an empty shell.
During one of the rare occasions Frigga's not there, Thor comes to Loki's chambers.
There's no trace of dust, their Mother making sure to keep everything intact, ready for use. Loki's always been obsessed with keeping his belongings and surroundings as clean and composed as possible.
Shelves filled with books circle the chamber, floor to ceiling, taking every piece of horizontal space. There's one lying on the wide windowsill, a piece of silk marking the place Loki's last stopped reading.
Thor feels like an intruder here.
He kneels down by the bed carefully, as if not to disturb his brother's sleep. As if it matters whether he's conscious or not. As if there's any difference.
Loki lies on his back with his arms by his sides and stares at the ceiling.
Sometimes his eyes wander and it always fills them with awful, painful bursts of hope.
'Brother,' Thor starts anxiously. His hands itch to grab one of Loki's, to feel the warmth radiating from him.
But there's none. He's tried this before. Loki's cold as a dead body.
'I don't know if you can hear me. Maybe I'm talking to myself. But if I'm not...' He pauses, throat constricting painfully. 'If you're still there... if there's any chance...'
Thor gets mad sometimes. That's how he deals with misery and fear.
He smashes things and screams and flips tables and drinks himself into stupor. Gets mad at Loki.
'Please, let me know. Let me know you are truly alive.'
Sometimes he cries. Cries and begs and prays fervently that this is but a trick, one of Loki's mischievous jests that used to irritate him so much. He'd give anything for this to be another malicious, troublesome scheme.
The Norns stay indifferent to his prayers.
'I need to know... know you're still there. I can't go on like this.'
His vision blurs with tears. They run hotly down his face, disappear into his beard. Thor grabs Loki's thin hand and presses it to his cheek, searches for the pulse frantically. It's there, calm and steady. Idle.
He starts to forget it had one day been anything but.
'I can't go on without you.'
Loki remains unmoving.
Years later, Thor will meet Thanos, the Mad Titan. And Thanos will say:
'It was so much fun breaking your brother.' And he will say: 'He resisted for much longer than I would've expected. Kept clinging to you stubbornly, silly little godling.' And there will be something akin to amazement in his voice.
And he will say:
'He actually thought you would come and save him. I made sure he understood that you would not, that there was no one coming for him. Ever. I made sure to etch it into his mind that no one cared enough, no one loved him enough, before I tore that mind to pieces.'
And he will say:
'You should've gone for the head.' And he will snap his fingers.
By the time Thor comes back to Asgard half of his people have disappeared, turned into dust. His little brother among them.
It doesn't hurt as much as Thor would expect.
The truth being Loki's already been gone for a long time.