A/N This is the "forced choice" whumptober prompt. Warning for character death.

He doesn't understand what's happening.

Everything had been going so well since they'd left Asgard. Their home was gone, but their people – or the ones who were left – were doing well. They were going to Midgard. They were going to see the Avengers. They were going to rebuild their home.

That's all gone now.

Thor had known, when he saw the look on his brother's face, that this wasn't going to end well; that these newcomers breaking their way into the ship weren't going to be friends. But it was a ship of Asgardians; a ship of gods with all the power in the world. He'd been so sure they would win. He'd thought it would be over in the blink of an eye.

And it was, in a way.

He blinked.

And now they're all dead.

"I know what it's like to lose." The voice feels faint, distant. "To feel so desperately that you're right, yet to fail nonetheless."

He doesn't understand what's happening.

He's not sure he's supposed to.

A hand – a big, strong hand – grabs him by the chest plate, and then the floor that's been holding him up so nicely disappears from beneath him. He groans with every step the man makes, arms and legs hanging down helplessly as he's carried through the ruins of the ship.

The man is still speaking. Thor can't hear a word of it. He feels like he's suffocating in the dense air around him, and he tries to bring his hands to his throat, to pry his chest plate away from his neck if nothing else, but every movement sends a new wave of pain through his battered body.

He's thrown back down to the ground, and he tries to use that, tries to force himself to his feet, tries to force himself to fight, but then a hand grabs his head, pulling him up to his knees and holding him tight. He grimaces, breathless, helpless...

And then he sees Loki.

He's alive.

He's unharmed.

He's surrounded by these men who have slaughtered half their people before their eyes, but he's unharmed. It's a cold comfort, but right now, any comfort is a welcome one.

The hand around his skull grows together; then, "The Tesseract..."

Is that what this is about? All of this death, all of this destruction, it's about the Tesseract? It's for nothing, then; a problem that could have been solved with a simple question. The Tesseract isn't here. The Tesseract may very well not exist anymore at all, after what Hela and Surtur have done.

"Or your brother's head."

Perhaps he should have figured it out before, but it's only now that he finally realizes what's happening. This man thinks that Loki has the Tesseract, and he's going to kill as many people has he has to to get it from him. Except there is no Tesseract...

And Thor will be the next one to go.

He tries to fight it. He tries to free himself. But he can't. The hand that holds him is too tight, too strong, and he's all but helpless beneath it.

And all the while, Loki just watches. His face is expressionless; unreadable even to his brother, even to the man he's spent nearly every day of his life with. Everything has fallen apart around them – their ship is falling to ruins; their people are dead; Thor may very well be next – and his face is just... blank.

"I assume you have a preference."

It's then that Loki finally speaks, eyes glued to the man standing above him. "Oh, I do," he says, and there's almost a smirk on his face, a taunting lilt to his voice that tells Thor exactly how this is going to go before he says it. "Kill away."

Thor hears himself cry out, but he can't bring himself to say anything; can't think of the words to say; can't think of anything but the utter betrayal he feels. His brother, his best friend, the only person who truly matters that the Norns haven't yet stolen from him, and he's giving him up – over nothing; a misunderstanding; something they don't even have!

A cold metal presses against his head, and then, it's as though all the power in the world begins to flood through him. It surges through every inch of him, an excruciating pain unlike anything he's ever felt before, and he's near-convinced it's going to tear him apart; that it's filling him so densely that his body will have no choice but to rip itself open to let it all out.

He cries out in pain, his eye rolling into the back of his head as this energy overwhelms his every sense, and it doesn't stop. It doesn't matter what he does; doesn't matter how much he screams; doesn't matter how hard he tries to squirm his way free. It continues to surge through him, burning him from the inside until he fears there will be nothing left of him when it's done.

"Alright, stop!"

It's Loki's voice that finally frees him from this personal hell. The power that had been flooding his body disappears, though the pain that came with it remains, and he finds himself groaning, panting, helpless, and the hand gripping his skull is the only thing that stops him from falling back to the floor.

"We don't have the Tesseract," Thor chokes out. "It was destroyed on Asgard." Can't they see how ridiculous this is? They're fighting for something that neither of them have; that neither of them will ever have.

It's the first that Loki's looked at him since he was dragged out here, and a look of guilt, of pain, of regret crosses his face before he raises his gaze to their foe's once more. He holds up a hand, and, without another word, the Tesseract materializes in it.

Thor can feel his heart drop.

He has it.

He has the Tesseract.

He's had it the entire time.

He's watched as the ship was torn apart, as their people were slaughtered before their eyes, knowing all along that he had the key to stop it, and he did nothing. They came here for him, and the whole of Asgard paid the price.

This is his fault.

Thor raises his gaze to his brother's, but Loki won't meet his eye. He's a coward, through and through. After all these years, it shouldn't come as a surprise.

"You really are the worst brother," Thor growls.

Loki lowers his gaze to the ground, head bowed in well-earned shame. "I only took it to follow you," he says. "It was my only escape from the vault as Asgard fell to ruin, and I took it to stay alive." He closes his hand, and the Tesseract disappears once more. He finally, finally raises his gaze to meet his brother's, and it's only then that Thor sees the tears welling up in his eyes. "But I'm not a fool. I know that some things are more important than my own life."

Thor can feel all the blood drain from his face. He doesn't like the sound of this. He doesn't like where this is going.

"Thanos can never have the Tesseract," Loki says. He raises his gaze to meet the Titan's. "It dies with me."

It all happens so fast.

Loki's blade appears in a flash of light, and before Thor's even realized what he's doing, he drags it across his throat, digging deep into the flesh and coating itself in blood. Loki lets out a choked gasp as he falls to his knees, and his blade falls to the floor beside him.

"No!" Thor cries, and he longs to run to him, longs to hold him, longs to save him, but he can't. He can hardly move, hardly think, hardly breathe as he watches his brother fight through his last moments.

In a rough movement, Thanos throws Thor aside, marching up to Loki instead. Thor screams, begging him not to, begging him to leave him alone, but his pleas fall on deaf ears.

"What did you do?" Thanos growls. He grabs Loki by the throat, blood coating his hand as he half-covers the gash without so much as a thought, and hoists him into the air.

"Loki!" Thor screams. This isn't happening. This can't be happening. His brother isn't dying. Not today. Not here.

Loki's face grows pale, the blood shining bright as it falls against his sickly skin. He meets his brother's gaze, and there's no desperation in his eyes; no silent plea for help; no hint of regret or uncertainty. He knows what he's doing, and though Thor wishes more than anything that he didn't, it's too late now. He knows that. He doesn't want to admit it, but he has to. It's too late.

Loki opens his mouth, and though no sound comes out, it's clear what he's trying to say.

"I'm sorry."

And then his body goes limp.

"Loki," Thor whispers. He almost can't believe it. He almost doesn't believe it. He's done this before. He's "died" at least twice this decade alone. He's always come back eventually. He always comes back.

... He doesn't know if he's going to come back from this one.

Thanos throws Loki's lifeless body to the ground with an aggravated cry, and Thor flinches at the fury in his voice. His brother's corpse now lies in a small crater in the floor, blood still dripping down the side of his neck.

A part of Thor wants to run up to him, to hold him close, to have one last hug from the most important person in his life. Another part wants to close his eyes, to look away, to pretend he doesn't see it. Maybe if he doesn't look, he can convince himself it's not real – that none of this is real; it's a nightmare and nothing more, and in only a few moments, he'll awake in his bed and realize none of this ever happened.

Thanos looks around the ship, his jaw clenched, his hands balled into fists by his side. But there's nothing he can do. Loki's gone, and with him, so is the Tesseract.

He lost.

Thanos lost.

But nobody's winning today.

With another cry of rage, Thanos kicks his foot forward into Loki's ribs, and his body is thrown across the ship, slamming into the wall with a loud thud.

"Stop!" Thor chokes out, his voice hoarse.

It seems that was a bad idea, because Thanos's gaze falls to him next, and Thor feels himself shrink beneath the fiery rage in his eyes.

Thanos looks to his men. "Take Loki," he orders them. "Kill the rest."

One of his men, his so-called children, tries to question it. "But, sire–"

Thanos cuts him off. "We will find the Time Stone, we will bring him back, and we will take what is rightfully ours."

Kill the rest hadn't phased Thor all too much. Even take Loki hadn't really registered. But this? He died to protect the Tesseract. He sacrificed everything. And in the end, it will all be for nothing.

That's what it takes to force Thor to his feet. He stumbles forward, his legs threatening to give out beneath him, but he won't let them – he can't let them. He has one chance to stop this. One chance to protect his brother and his sacrifice. One chance to–

Thanos grabs him by the neck and hoists him off the ground. "Let this be a lesson," he growls. "This is just a minor hiccup in a plan fated to succeed."

Thor squirms beneath his grasp, limbs flailing helplessly, and the grip around his throat only grows tighter. Thor chokes out a gasp, his movements growing more frantic, arms reaching for the Titan's fingers as though he can pry them off, but to no avail.

"We will save this universe," Thanos says, "and nobody can change that."

The world begins to feel blurry, all the sights before him blending together. His limbs begin to tingle; his head begins to feel faint. He needs to take a breath. He needs to free himself, and he needs to take a breath. He needs–

The hand grows tighter once more, and a searing pain shoots through him.

"Let this be an example for anyone who dares try to stand in our way."

The hand grows tighter still.

Crack.

And the world goes dark.