AU all the way: Thor - Set before the movie. KH - Post Kingdom Hearts II, and I'm taking some liberties. =P
Aesir Hearts
At first, there were one or two, easily dispatched when they proved to be bothersome. Then there were five. Ten. A thousand.
A flood.
Asgard's warriors turned out in full force, led by their golden prince and his sorcerer brother.
Thor's hammer flew, scything down countless shadows, but their ranks did not diminish. Loki's magic rolled out in waves of pure destruction, but still the shadows came.
Warriors fought and fell around them. Grim-faced, Loki sent his magic out again and again, drawing heedlessly on a well of power that that had never before run dry, until at last even his vast resources started to fail, and still he fought.
And at the end of his magic, Loki found ice. Frost cold as the spaces between realms came to his call, cracked the earth with ice, leeched motion from distorted limbs black as night.
He saw his skin go pale as death, then blue. It mattered nothing, not here, not now. Drawing on reserves he hadn't even known he had, ice flowed forth from Loki in a torrent, seeming at last to slow the invaders.
Thor fell back to stand, breathing hard, at Loki's side. The brothers looked at each other. Fandral had fallen. Volstagg and Sif had grievous wounds, and Hogun was nowhere to be found. The warriors of Asgard were decimated, and Odin and the einherjar were barely holding the castle.
Loki tasted death, and knew that even he and Thor together would not be enough to reach the source of the invasion, the open Bifrost. They would die here. He saw the same realization mirrored in his brother's face.
There was nothing to say. The brothers reached out, clasping each other's forearms in a warrior's greeting and farewell.
Once more they turned to face the swelling black tide.
"For Asgard!" Thor yelled, raising Mjolnir over his head.
"This is insane, I'm insane," Loki muttered, even as ice leaped to his beckoning call, swirling frozen shards of death around him.
The tide of yellow-eyed invaders swelled hungrily towards them, ready to devour them, and a white-haired figure slipped past them, running flat out towards the invaders.
"Sin Harvest!"
Pillars of black light boiled up around the man, scorching back the invaders and making the tide recoil for a few precious seconds.
Green light flowed over the two princes, healing wounds and salving fatigue, and Loki thought he heard a light female voice somewhere in the background. Then a second figure was streaking past them, brown hair in disarray.
"Firebird!" the second man called, hand raised and clutching some form of glowing jewel. Immense magic coalesced out of the air, the force of it swirling heavily, eagerly into the form of a giant bird of molten lava. The summoned spirit screamed in mindless avian fury as it burned a wide swath down the Bifrost.
"That should give us a bit of time," a young woman said, jogging up to stand between the two princes. "Hello. My name is Kairi," she nodded. "That's Sora," the young wild-haired man, whipcord lean, grinned, "and Riku," the taller white-haired man, of an age with the first, nodded, offering them a half-salute.
"I am Thor, son of Odin, and this is my brother, Loki," Thor offered. "Do you know what these things are? And how to stop them?"
Without batting an eye at Loki's appearance, the brown-haired warrior, Sora, nodded to both princes. "Yeah, we know what they are. They're called Heartless, and-"
"And we're running out of time," Riku prodded pointedly.
"Er, right," Sora nodded. "Look, has anyone with a really strong heart, or, hmm, spirit, gone missing in the past few days?"
"Many have gone missing," Thor admitted, then sucked in a sharp breath. He shared a stricken look with Loki, who had made the same connection. "But… By far the strongest spirit… Heimdall. We've not seen him for days."
"Who's Heimdall?" Riku asked sharply.
"One of the strongest of the gods, perhaps stronger even than Odin Allfather," Loki said flatly. "And the Guardian of the Bifrost Bridge, which opens paths to all other realms."
Far out at the tip of the Bifrost, something roared. Loki could feel the surge of energy all the way from where he stood near the drop-off into the wildly foaming waters.
"hlk." Sora opined.
"We may need backup on this one," Kairi allowed, frowning.
"Hey Riku, how soon do you think you could get Sephiroth here?" Sora asked, looking nervously at the distant point of the bridge.
"Soon," Riku quirked a smile and stepped into shadows that disappeared behind him.
"What was that?" Loki asked sharply, unfamiliar magics acrid on his tongue.
"Don't worry, he'll be back," the young woman said, sidestepping Loki's question. On the other hand, Loki was hardly in a position to look this gift horse too closely in the mouth. For now.
"We'll keep the pipsqueaks busy while we wait," Sora grinned, raising a very impractical-looking black sword. They'd need to, Loki saw. Already the invaders were massing for another attack.
"I like the way you think," Thor grinned back at the newcomer and hefted Mjolnir.
Loki rolled his eyes. Well, at least someone was having fun.
Sin Harvest – Sephiroth's Darkness attack. Riku learned it from him post-game, says my head-canon.
Firebird – non-canon summons, the magma-phoenix from the last piece of Fantasia 2000.
Assume KH Trio are late teens-ish.
