He regains consciousness slowly, the searing pain along his left side creeping into his awareness. Detachedly, he realizes that this means his wounds must be far worse than what he felt while receiving them. His need to aid Thor during Thanos's attack must have numbed him. That – combined with the force of being thrown clear across the room, and then skidding along the broken glass and other debris on the floor – must have knocked him out completely.
Though he wishes he could continue to drift in mindless, painless oblivion forever, he forces his eyes open. He cannot give up yet.
As soon as he opens his eyes, though, he wishes he never had. The remains of the Asgardians' stolen ship seem to tilt and waver before him, his head pounding. Sparks fall from broken pieces of machinery while evacuation lights flash.
He is surrounded by countless bodies – women, children, the elderly. Some are even familiar faces from his youth. They are the bodies of all the Asgardians he had fought so hard to save mere days ago, arms outstretched as they came running to him, calling, Your savior is here!
He had finally given the role of the hero a chance. For the first time, he had gladly embraced the possibility that he could be something more than mischief, just as Thor had always believed. And for what? What good has it done him now? Destruction follows in his wake even when he resolves to fight against it.
He should have disappeared when he had the chance. Asgard has always been better off without him.
You know that's not true, a voice that sounds much too like Thor's whispers in his mind. You are a prince of Asgard. They will always need you. Stand up, Loki, and fight.
Gritting his teeth, he leans all his weight onto his right arm, slowly forcing himself to rise. Dizzy, he sways on his feet for several moments, blinking repeatedly to clear the spots from his vision.
Breathe, he commands himself, hoping to calm his racing heart.
He can admit to himself that what he is about to do terrifies him. He has faced great foes before – faced death too many times to count – but this is something else entirely. It is not the instinctive sacrifice he made on Svartalfheim, nor the hopeless resignation he felt while hanging above the Void, fingers ready to let go.
No. This is different. Even on the slim chance that his plan actually works, he will never be able to undo its consequences.
This is a hero's choice, he thinks.
He takes one step, then another, ignoring the blood he can feel sticking to the shredded leather along his side. He passes over each Asgardian almost reverently, each face hardening his resolve and convincing him to keep moving forward.
"Thanos."
His hoarse voice barely carries in the cavernous space, but he knows the titan will hear his call. Never before has he dared to use the creature's name – first, out of fearful obedience; later, to avoid being found and punished for his failure on Midgard.
Now, with Thor lost in space, the Avengers scattered, and his people dead around him, what has he to lose?
In just a few seconds, Thanos himself appears before him, stepping out of the portal he has created with a disturbing, familiar grin. Loki freezes in place, chest heaving from a mixture of pain and dread that he desperately tries to ignore.
I have no other choice. I am their last hope.
He almost smirks as the thought crosses his mind. The realms are surely doomed if he is the only one left to save them.
This is a hero's choice, he repeats to himself, taking a deep breath.
Tugging at the last shreds of his magic, he pulls the Tesseract from its hiding place, holding the cube in his bare hand. He lifts it slowly, turning his shaking palm upward and standing straighter as its cold power washes over him. Thanos takes a hungry step closer.
Loki lifts his head defiantly, bracing himself. "This is one Infinity Stone you will not have," he whispers.
Before Thanos can stop him, Loki slams the Tesseract against the ground, its protective cube shattering into hundreds of crystal shards. The Stone within bursts free, blinding him with its electric blue light. He reaches out with everything in him, grasping at the essence of the Tesseract and dragging it into his being.
It feels as if he is being torn apart from the inside, the Tesseract's raw power worse than a thousand knives being driven into his body. He drops to his knees, mouth falling open in a silent scream. Barely able to form coherent thoughts, he squeezes his eyes shut. How did Thor's mortal possibly survive an experience like this? How did the Aether not destroy her the moment she touched it?
Just when he is certain that he has made a terrible mistake, everything stops. For a moment, he simply remains still, desperately trying to catch his breath.
Then, he opens his eyes.
The Tesseract's power thrums through his veins. New strength pours into his limbs, his wounds healing faster than they ever have. Streaks of color flash across his vision, illustrating energies and auras he had been blind to before this moment.
He feels better – greater – than ever before. He feels unstoppable.
More than that, he feels infinite.
Grinning, he stands.
There is a war to be won.
A/N: Loki cannot die in Infinity War. End of story. He probably won't get this kind of revenge on Thanos, either (not to mention that the Tesseract may not actually work like the Aether), but we can dream, can't we? :P