Note: This contains major spoilers for Infinity War. You've been warned.

Thor has watched his brother die once before.

He remembers all too clearly: Loki stabbed through the chest, then gasping for breath on the ground as he faded to ashen grey.

"I'm sorry. I'm sorry."

Loki isn't sorry for this.

He glares Thanos down even when he knows he's defeated- even when he knows he's going to die. Even when Thanos's hand is around his throat, even as the God of mischief struggles to breathe, he taunts the Titan.

"You will never be a God."

For once in life Loki has chosen a side. For once in his life he is doing the right thing, he is certain of it, and he is more than willing to die for the side he has chosen.

For so long Thor wanted Loki to fight by his side. He wanted his brother to choose a side.

But Thor is far more panicked when he sees the dagger than when Loki pledges his allegiance to Thanos.

Why does he have to choose a side now?

There is nothing Thor can do to stop him. He is gagged and bound, and the slightest reaction on his part could cost his brothers life, or save it. He tries not to react more than he can help it, but he wants to, desperately.

"Loki, no! Brother, don't!"

There is nothing he can do but watch.

It happens so fast. Loki lunges for the Titans throat, but the dagger freezes, and then he's dangling from Thanos's hand, struggling vainly, and then there is a sickening crack—

Thor can't even scream.

Loki is dumped in front of him like a broken toy, and Thanos leaves them both to die.

For days Thor has thrown rocks at illusions, hoping for them to be real. Now, as he crawls to his fallen brothers side, he wishes it could all be an illusion.

But it isn't.

Loki is solid, and real, and broken, and Thor buries his face is his shirt and sobs.

He's still breathing.

Thor pulls away instantly, and looks down at Loki in disbelief.

His breath is thin and rasping. His eyes are glassy and bloodshot, and ringed with tears.

"Brother-" He chokes, "I'm sorry."

Loki's expression is the same as the last time Thor watched him die, desperate and accepting- but this time it's real.

Something inside of Thor shatters.

"No." Thor grasps his arm as if that will hold him there. "No, no, no-"

"I'm sorry." Loki repeats. His voice grows more frantic. "I should've been faster. I should've left the tesseract. I should've-"

"It's alright. You're going to be alright."

"No."

Thor's voice breaks as he repeats his brother words, and tries to believe them.

"The sun will shine on us again."

Once Thor's grief might have amused Loki. He watched from the shadows as his brother mourned him once, and felt a strange mix of guilt and satisfaction as he heard him scream. Thor did care. Someone cared.

But many things have changed since then, and Loki does not wish Thor to suffer such grief, especially not when he knew what his choice would cost.

"The sun will shine on you again." Loki says, and the light is eyes turns mischievous as he smirks. "Get help."

Thor laughs brokenly, and Loki's world goes dark.