This is the first fic in what will hopefully become a series of connected shorts in an ATLA fusion verse! (The tumblr tag is ouatla, please come geek out with me on the awesomeness of all possible versions of this AU.)

Still contemplating the time travel aspect, so for now I'm saying that this is set generations after the Fire Nation attacked. Milah is an airbender, a descendant of one of the few who escaped the massacres by virtue of being somewhere else and then hiding.

In this universe, Bae died young at the hands of Fire Nation troops; if Neal shows up he'd be a different person. Henry is not her son - he is, like Milah, a lost airbender. Emma is of course the Avatar (…also NWT princess), and is a few years younger than Killian, who is still early twenties in here, so he still gets a good few years of revenge-seeking in before they meet. Not that any of that happens in this particular fic.

If any of this background changes with a future installment, I'll update here to fit.

The moon is bright and full above them.

It's a warm night, but Killian feels frozen, deep inside, and his limbs won't move. He doesn't know what's happening, at first - tries to jerk back into motion, but something invisible is holding him still, it feels like an icy grip around his very heart itself.

"Where are my manners, we haven't been properly introduced. Rumplestiltskin! " Milah's husband says, throwing his arms out in a dramatic bow, but his fingers twitch and Killian can feel himself moving, jerking forward in a return bow entirely out of his own control. The waterbender follows up with a wicked grin: "Or as others know me, bloodbender."

Killian can hear his men shifting back behind him. He lifts his head - he's being allowed to do that - and looks the man in the eyes.

He's heard stories.

They circle in the Fire Nation Navy, tales of South Pole raids gone wrong when soldier and firebenders alike froze in their tracks. Stood still and accepting of their slaughter, or even turned on their own people, controlled as if puppets guided by the hand of some evil spirit. Or not a spirit, some whisper, but a form of bending more terrible, more heartless than even lightning, and more impossible to fight.

Of course, those in charge say bloodbenders are no more than a myth. The Water Tribes are a stupid, barbaric people, with little to offer the world beyond seal blubber and parkas. Their bending is weak, undisciplined and ineffective and there is no possible way they could ever be more dangerous than the prized technique of the royal family. Fire Lady Regina would personally kill any man who suggested otherwise, without blinking. Bloodbenders don't exist.

Killian hasn't believed any of those lies in a long time. And now his body is not his own, he cannot move at all no matter how he struggles - until suddenly, the spell lifts. His chest expands in a deep breath, and he can feel the heat waiting, but the moon is still full above them and the bloodbender is smiling next to him.

Rumplestiltskin leans close to ask, "How's Milah?"

In so many ways, this man is vastly different from the wreck Killian once challenged to duel. He's standing tall, no sign of a limp, he's dressed in a scaly blue so dark it looks black and his voice is too confident, too mad. And Killian's breath is suddenly leaving a fog in the air, his blood feels like it is boiling in his veins; he laughs. "Who?"

Rumplestiltskin giggles . "Only too happy to, uh - dig out the memory… but! It gets really messy."

The smile on his face is crooked, the look in his eyes distantly happy, as if reliving a fond memory. Killian thinks of sharp ice in dark waters.

"She's dead," he says, and stands tall. "Died a long time ago. What is it you want?"

There's a long pause. Killian breathes in slowly, stoking the fire in his lungs.

"We didn't get a chance to finish our - what did you call it? Agni Kai?" The scorn drips from his words and Killian flinches, flame flaring to life in his hand in that instinctive defense of his home he's yet to lose.

"Not now, tomorrow at midnight," the bloodbender cries, and every dramatic movement of his arms has Killian tensing more, fearing that suddenly his limbs will once again be out of his control. He's certain it's intentional. "I am not a cruel man, get your affairs in order. Also! You can spend tonight knowing… it'll be your last."

His smile is darker than the deepest ocean. "Hmm, maybe I am cruel. And don't think about trying to escape," he steps in close and Killian's body stiffens, the fire on his palm snuffs out, he is nothing but a puppet, again - "because I will find you, and I will gut your entire crew, like a skunk fish."

Killian cannot move until long after the man has disappeared into the shadows.

-xxx-

He's helpless.

His body jerks, first obeying him, then suddenly stopped, his flames gutter out before they leave his palms as the bloodbender dances freely around him. There's ice, and cold water drenching him, and then it's gone again and the man is just standing there, grinning wide like the serpent-skin he wears now.

This duel could never have been fair, not at midnight under a full moon, but Killian couldn't argue at the time it was uttered. Wouldn't if he could, his own challenge had been at noon on a sunny day – but he'd said he had a duty to bring Milah back home with him, he'd all but laughed over what could be done to her, and still her husband had not fought.

Now, though - he's toying with Killian, that much is obvious from the start but there is nothing he can do but fight on, try to battle the cold that seeps deep inside of him, try to get closer, to burn hotter and faster and maybe he can take advantage of one of the moments Rumplestiltskin lets go to -

His leg gives out in the middle of what should have been a powerful fire kick, and he falls to the ground. Above him stands the bloodbender, the serpent, with pools of water floating around his outstretched hand.

He twists his fingers, and the water sharpens into daggers of ice.

Killian thinks of Milah, left unawares on the ship.

"Go on," he demands, "I'm ready for the spirit world."

The shards hover closer; halt scraping against his neck. "…no," the bloodbender hisses. "Do you know what it's like? To have your wife stolen from you by a damned firebender? To feel powerless to stop it? It feels like having your heart frozen, shattered in your chest. Actually," he reaches forward, "let me show you."

Killian takes a deep breath, thinks of Liam and Milah and they fill him with more warmth than Agni ever could, even in these last moments, with that deep deep cold filling him inside, that agony, so cold he's burning from inside out -

"Stop!" Milah yells, and a harsh gust of wind knocks the bloodbender off his feet.

-xxx-

"That first night, when Killian and his crew came into the tavern, he told stories about the places he'd been, and I fell in love with him," Milah pleads. There's a sharp sort of twist in Killian's chest, his heart beating out of control, and she's begging again, desperate, "I didn't mean for it to turn out this way! I didn't know how to tell you the truth, I'm sorry!"

Killian can't breathe steady enough to stoke his inner fire. He is lying on the cobblestones shivering, teeth chattering, and still unable to move as Rumplestiltskin takes a deep, slow breath above him.

"And so here we are," the serpent exclaims. "You've come to save the life of your twoo wuv , the firebender. I didn't realize the power of true love before… Conquering over the genocide of your people, it is impressive, I'd hate to break it up. No, wait. I'd love to."

As always, the mention of his people's crimes burns Killian, robs his breath and fills his mouth with ashes. He is not surprised the serpent used this argument, it is far from new to him. And the things he himself has done, the battles he's fought before Liam was - he may not have committed the genocide himself, but it hardly matters. Firebending is not inherently evil, he still believes that - but Killian himself is so far from clean.

But, to say such a thing to Milah - she has spoken to him of her childhood. Of her parents, always telling her to hide, hide, and run if ever she so much as lifted an accidental breeze around the wrong person. Of those parents dying by a fiery hand, of being alone in the world with no one to trust, perhaps completely alone and if there were others she'd never know. Of longing to travel, to search for more of her people, to indulge in her gifts without fear, to be free as she was always meant to be. Her spirit is air itself, she was never meant to be caged in ice - and still, for all the love between them Killian knows how much it hurts her sometimes, to love a man with fire on his fingertips. Knows that she struggles with that betrayal every day, just as she struggles with leaving Bae even if it was so much safer, better for him there…

That this serpent brought up the Air Nomads to Milah makes Killian hate him far more than any bloodbending ever could.

But she is strong, so strong, she doesn't spare more than a single shaky breath to the taunt before reaching into her pocket and withdrawing a red ribbon with black edges. Killian recognizes it instantly, knows that it is from the war plans they've worked so hard to get and it's immediately clear Rumplestiltskin does too. She bargains for his life, their lives (she says like it should be taken for granted, even though she could have been safe if only she didn't come after him, and Killian's heart aches for reasons entirely independent from the bender standing over him) and succeeds, against this madman, against this man who held her back for so long.

She is so strong, she is beautiful when she tugs him back to his feet after Rumplestiltskin has gone, and Killian can feel the breeze at his back helping him up, pushing him right into her arms, and she kisses him so hard it hurts.

She doesn't yell at him for what he almost did tonight, though he knows she wants to; instead, her fingernails leave cuts on his hand from how hard she grips it leading him back to the ship. When he glances over to her, she is staring at him like she's trying to memorize every moment.

Later, Killian wishes he'd done the same.

-xxx-

Milah tosses the scroll at him before Rumplestiltskin can snatch it; it flies through the air on a breeze more buoyant than should be possible, and as always her bending makes Killian fiercely proud. It's gratifying to see the bloodbender twitch, as though he's still uncomfortable with the easy display of airbending – no surprise, given that he never allowed her to practice it even in the safety of his tribe.

"Do we have a deal?" she asks. "Can we go our separate ways?"

"Do you mean, do I forgive you? Can I… move on? Perhaps, perhaps," claims the serpent, pacing away along the ship. His dark garments render him almost invisible in the night; Killian lights a fire in his right hand, and sees the man twitch again. "I can see you are… truly in love."

"Thank you," Milah says, relaxing too soon.

"Just one question."

"What?"

"How could you leave Bae?" the bloodbender asks, and suddenly the air is getting cold again. He carries on, the sea growing restless beneath them, rocking the ship dramatically as he ignores Milah's attempts to calm him – "Do you know what it was like, walking home that night? Knowing I had to tell our son that his mother… was dead. I could never tell him the truth of what you did."

"I was wrong to lie to him, I was the coward, I know that-" Milah says, and her voice is trembling, this is every late-night confession that should not be forced out of her by this cruel man.

"You left him, you abandoned your family!" the bloodbender shouts, and a wave hits the side of the ship high enough to spill over onto the deck, splashing them all.

"And there's not a day that goes by that I don't feel sorry for that –"

"Sorry isn't enough! You let him go."

"I let my misery cloud my judgement," Milah hisses.

"And why were you so miserable?"

And Killian knows – the Jolly is rocking wildly now, the scroll in his hand is getting crushed in his grip because he knows suddenly what is going to happen but he isn't fast enough to stop it –

"Because I never loved you!" Milah screams, and a burst of air explodes out from her, a furious, undirected rush of power. "You never let me be who I am!"

The serpent lifts his hand towards her, it seems so slowly…

"No!" Killian screams, but the fire in his hand dies before he can throw it, his entire body is suddenly frozen again, locked in place by the bloodbender's other hand, gripping at the air.

The hand in front of Milah grasps, like claws –

"NO," Killian is screaming, again, but there's nothing he can do he can't move he can't bend he can't save her

Milah looks at him. "I love you," she whispers, the air carrying her words to him soft and low.

– and the bloodbender's hand rips inward, clenches shut and Milah, Milah goes limp, suddenly, Milah is gone, Killian can feel the exact moment she goes.

She was the air that stoked his flame and he can feel it in his very soul when she goes out.

The bloodbender releases him again and he stumbles forward, catches her before she hits the deck and lowers her slowly. Smooths his hand across her skin, and – trembles, everything in him is shaking, he is lost and the fire within him is building.

"You may be more powerful now, demon, but you're no less a coward!" he shouts, rising to his feet. There's a wildfire in his heart, burning up everything it sees, and tongues of flame leak out with his words.

"I'll have what I came for," the serpent says, calm as empty ice, and Killian will shatter him.

"I'll die first!" he yells, and lets the heat raging within him out – fast, and precisely aimed, because he knows what this monster can do.

The scroll in his left hand is reduced to ash in a second.

"You," hisses the bloodbender, and just as sudden, there is a flash of water, so cold it burns and Killian's – his hand is on the floor. It's been sliced right off, and he can't help the cry of pain, clutches the stump against his chest and falls to his knees by Milah – by her body.

Rumplestiltskin picks up his hand. Ice spreads over it, freezing it instantly. Killian is – he recognizes this now, this awful feeling of lost control, he knows even before he tries to move and fails. He is the bloodbender's puppet again.

His stump lifts itself up in front of his eyes. He's shaking uncontrollably, watching it bleeding out and unable to do a thing about it, Milah's body right next to him and the moon high above.

"I want you alive," the serpent tells him. "Because I want you to suffer, like I did."

He releases his hold with a twist of his hand and turns to walk away.

He's giggling.

Killian rises to his feet with a roar, falling into the most basic and powerful form he knows, and throws his whole self into – a single, pathetic wisp of orange.

"Can't bend without this?" The bloodbender waggles the frozen hand in his grasp, and laughs. "Killing me is gonna take a lot more than that, dearie."

And Killian – has lost everything, every single thing that – Milah at his feet, and no fire in his heart, and his arm is bleeding out, but he is not lying when he says, "Even demons can be killed. I will find a way!"

"Well, good luck living long enough," Rumplestiltskin sneers, and then he's gone, over the side and away into the waves.

-xxx-

His first mate cauterizes the wound he can't, with a sharp hot burst of agony (but the pain isn't why he's screaming).

They set sail immediately, to the nearest Air Temple – Killian will not bury Milah in the ground, cannot burn her and would never give her to the water now.

It takes nearly a week to reach the Southern Air Temple, and it is already a graveyard of blackened bones. Killian leaves his crew behind and goes up alone with Milah in his arms, carries her past all remnants of battle, up to the highest point he can find.

Her body is already starting to smell. His shortened arm gives out more than once, and a third of the way from the top, he vomits from the combination of pain and stench.

Finally, he lies her down on a flat rock.

"I love you," he tells her, and turns to go. "May your spirit always be free."

Sailing away, he watches the vultures start to circle.

And for the first time in years, he prays to Agni: for fire, for hatred, for revenge.