Two Faces: All the reasons Alluka loved her big brother Killua from the beginning, and all the reasons Nanika learned to love him too.

Alluka loves her big brother because he was the first one to smile at her.

Her first memories, from when she was just two or three, are filled with people in dark suits, who are kind but very distant. When she cries for something, if she's hungry or cold, they give it to her. That's good, but she doesn't like the way their eyes dart around, as if they were afraid of something. That scares her, too. She doesn't like being around people who are frightened all the time, and she wants someone to play with her.

All she knows of her mother is a few glimpses of a visor-covered face and a mouth twisted at the corners in displeasure.

Her father, she sees only rarely. He is so big, all she can think is that it would be fun to climb up his hair and sit on his head. But he's cold, too, and she doesn't dare do anything when he looks at her. Her knees shake when he pats her on the head and calls her "My good son," and she doesn't dare correct him.

Her siblings don't seem to like her much, either.

Big brother Illumi regards her dispassionately when she first meets him.

He's just come home from a mission, and his clothing is impeccably clean, but for some reason he still smells like blood to her. His eyes are dark, dark, dark and empty, and she worries if she looks him in the eye for too long, she'll fall in to that emptiness. She is cold for a long time after he averts his gaze, and that night she shivers as she goes to sleep.

Milluki is mean, plain and simple. Alluka isn't afraid of him, though, so she likes him a little better than Illumi. He's always shouting and his voice his scratchy and he pushes her out of the way when he's in a hurry. He doesn't like her at all, either. He thinks she's an annoyance. The only person Milluki really loves is Mother, and Alluka doesn't think Mother loves him back at all. Sometimes she pities him a little bit.

But then she meets Killua.

Killua is nice; he smiles at her and holds her hand.

His eyes are blue, like hers. They aren't empty like Illumi's or angry like Milluki's. When she looks him in the eye she can see what he's feeling, because even if he smells like blood too sometimes, he isn't hollow and twisted like Illumi. He's a little shy and quiet sometimes, but when she asks him to play with her he nods his head and takes her hand.

And his smile is a very nice one, because she knows he means it.

Alluka loves Killua because Killua loves Nanika.

She doesn't make requests of him- the wish-power doesn't want her to ask things from her family. It wants something else from her family, but she isn't sure what. She doesn't think her family is giving the wish-power what it wants, except maybe for Killua.

Because she doesn't make requests, it's a while before Killua sees Nanika- back before Nanika has a name, Alluka calls her the Other.

They're playing in the forest, and a butler has finished paying for the last wish ("Go away, Alluka," made by Milluki without even looking at her) by lifting her up into a treetop.

The Other comes out to give a wish.

The butler flinches and cries out in shock. The Other doesn't blink. She doesn't know this butler or care much about him, so she isn't hurt by his fear. She loves him, just as she loves everyone, and she wants to make him happy.

Killua hops down from the tree. "What's wrong?" he asks the butler curiously.

Then he glances at the Other.

He furrows his eyebrows in concern, looking a little confused. Then he turns to the butler. "Go back to the house," he says. "Don't tell Mother about this."

The butler scurries off, looking horrified.

Killua turns back to the tree. "Alluka, are you okay?"

The Other tilts her head.

"Can you come down from the tree?"

"Aye," the Other says, and hops down. Killua catches her and sets her on her feet.

Then the Other closes her eyes and Alluka opens them.

"Her name isn't Alluka," she informs him. "I'm Alluka, and she isn't me."

"Oh," Killua says, sounding a little uncertain. "What is her name?"

"She doesn't have one."

"Is it all right if I call her Nanika?"

"Call her 'Something'?" Alluka asks. She considers it. The Other likes the sound of it- it sounds a little bit like 'Alluka', and the Other loves Alluka. "I think that's okay."

"Is Nanika…" Killua hesitates. "Is she always there?"

"Yep." Alluka sits down and hugs her knees. "Nanika loves everyone. So she gives people wishes."

"Can she hear me if I talk to you?"

Reluctantly Alluka shakes her head. "I don't think so. If I'm here, that means Nanika is in the other place. She knows you're there… but hearing is hard."

"Is there a way for her to come out?"

Alluka looks at Killua in surprise. No one ever wanted Nanika to come out. They all wanted her to go away and never come back. They were scared of her, scared of her black eyes full of hope, scared of the wishes she gave.

"I think so," she says.

She can. She tugs at Nanika, and she goes into the other place, and Nanika switches with her.

She doesn't know what Killua says to Nanika.

When Nanika goes back into the other place, one thought is filling her blackness with happiness. Alluka catches it as they switch, and it delights her too, though it doesn't much surprise her. Killua has always been the best big brother.

Nanika loves Killua.

And Killua loves Nanika.

Alluka loves Killua because he knows without her telling him.

From the very beginning, he knows that she's his sister.

His "very favorite sister," as he tells her teasingly.

She wrinkles her nose and giggles and points out, "I'm your only sister, silly."

Killua laughs.

A few weeks later, he overhears the butlers calling her 'Young Master.' He stops in his tracks and turns on them with angry blue eyes and scolds them fiercely. How could they address a young lady like Alluka so rudely? He lectures them on manners until they're all kneeling at his feet asking his forgiveness.

"You don't need my forgiveness," Killua says. "You need her forgiveness."

Alluka pokes her head out from behind Killua's knee, feeling warm inside. She'd never told anyone. She was so scared of Illumi and Mother and Father and Milluki and even when she wore dresses everyone thought she was just like Kalluto, but Killua knew, and he loved her.

"We're deeply sorry," Gotoh says, and he sounds sincere. "Please forgive our failure."

Alluka ducks her head. "S'okay," she says quietly.

As she and Killua walk away (Killua is still muttering angrily under his breath) she squeezes his hand.

He looks down at her. "Alluka?"

"You're my favorite big brother, too," she confides. "I love you."

Killua's eyes widen. Then he smiles. "I love you, too."

She learns later that it doesn't stop with the butlers. Illumi-nii scoffs at Killua for "wasting time going along with Alluka's whims, when you could be training."

Killua turns and stares at Illumi with blue eyes like ice.

"Don't you dare call her a waste of time," he snarls. "Don't even think it."

Illumi regards him, and his eyes are empty, empty, empty.

"Don't get so attached to your things, Kil," he says at last. "You never know when they could break."

Killua shudders. Then, with a pained look in his eye, he takes Alluka by the hand. "Come on, Alluka," he says, not looking away from Illumi. "Let's go."

Alluka looks back as they leave.

Illumi always says she doesn't have a soul. She doesn't know what he means by that. If having a soul is something that makes your heart feel full, she has one. Her body has two: Alluka and Nanika, filling up to the brim with darkness.

She thinks he has it wrong.

Illumi's shadow is empty.

Alluka loves Killua because Killua guessed right.

Nanika is special. Alluka knows that other people don't have Nanikas. She doesn't have to see that other people don't give wishes or make requests. She doesn't have to see that their eyes have a full blackness (not the empty blackness like Illumi-nii, never, never the empty blackness). She knows that other people don't have Nanikas because Nanika is, quite obviously, one of a kind.

Nanika is always there, even when she doesn't come out.

Nanika loves everyone.

She wants to make everyone happy. That's why she gives them their wishes- because that's the only thing she knows how to do to make people happy. She gives them what they want because she knows that people are sad because they don't have the things they want.

Nanika has always been the giver.

Alluka is the taker.

Alluka never understands why the butlers flinch in horror when Nanika comes out. Nanika has never done anything but give and help people.

It's Alluka who does the taking. It's Alluka they should all be afraid of. Because Alluka knows that wishes have a price, and she has to demand the price. She doesn't make requests because she wants to make people sad. It's just how things work. There is no 'if she chose not to make a request', because there is no choice.

Nanika's blackness is full of sorrow sometimes.

But Killua guesses right.

"Nanika," Killua says. "Wake up."

Alluka smiles and closes her eyes. Nanika opens them.

"Aye, Killua," Nanika says.

"Nanika," Killua says, "Heal the bird."

"Aye." And Nanika does. The bird lifts its head and glances around. At first it looks a little dazed, but it pushes itself up unsteadily. It shakes out its wings. After a few moments, it flaps them and lifts off, making a crooked line for the trees.

Killua pats her on the head and smiles at her. "Good girl, Nanika."

Nanika smiles. Her darkness is full of happiness. "I love Killua," she says. "I love Killua."

Killua nods seriously. "I love you, too."

Alluka is on the other side, but she smiles too. Because Killua guessed right. Killua answered the question about Nanika.

Nanika's eyes slide shut: she is tired.

The power has rules, but the rules are different for Killua.

For most people, there is a wish and then three requests. If the requests pay for the wish, Nanika gives out another wish. If the requests don't pay for the wish, the wish-power will make sure the wish is paid for in another way. Alluka doesn't know for sure, but she thinks lots of people die.

For Killua, the rules change.

Because Killua loves Alluka and Nanika with all of his heart. He loves them so much that he doesn't need to ask for a wish. He can just tell Nanika what to do, and she will do it, with no price or request or sacrifice or payment, because Killua's love is worth far more than any wish. Nanika will give him whatever he wants, because Killua is the only one to truly love them.

Nanika loves everyone.

That's why she lets people make wishes. She makes impossible things happen to make people happy. She asks people what they wish for, and it happens. She doesn't understand why people are so surprised when they find out that her wishes aren't free. She doesn't understand why they don't understand that wishes don't happen for nothing.

When people make Alluka happy, Nanika will make them happy. Because Nanika loves Alluka most of all, and nothing will ever change that.

Nothing, ever.

That was before. But now, things are different. Nanika still loves Alluka more than anything. She still wants to make Alluka happy.

Now, Nanika loves Killua, too.

Alluka loves Killua, even though he left her.

She doesn't know why he left, and she doesn't know if he's coming back. All she knows is that Killua got angry at Mother and stabbed her in the face and ran away from home. Mother was so happy she cried. Milluki-nii shouted at the butlers for hours before anyone thought to find Alluka.

She doesn't know whether he forgot all about her, or whether he doesn't love her anymore. She doesn't think that's true, though, because Alluka trusts Killua and he's always been the big brother who protected her.

With Killua gone, they had no reason to let her be free.

She loves Killua.

Even if she's wrong, she'll still love Killua.

She clings to that thought when Mother and Father put her in the room full of toys, with cameras to keep an eye on her. The room is comfortable. She is given anything she wants. The food they give her is good. The bed is soft. The clothing is clean. She is a bird in a gilded cage.

She can't go out. They will never let her out.

The room is silent.

Alluka sits among all the beautiful toys and does not cry.

She is not alone. She can never truly be alone, because Nanika is always there, filling up the empty parts of her mind. Nanika doesn't come out much, because there isn't anyone to fulfill the requests or make wishes. But somehow she still feels alone, and she doesn't think there's anything she can do to stop it.

Days pass, marked only by the artificial lights dimmed for the night. She loses count. She doesn't know how long Killua has been gone, but even though it feels far too long, every time she hears the click of footsteps outside the door, she hopes it will be him, walking in the door to carry her away- or at least play with her. At least talk to her. At least pat her on the head. Anything.

The room is empty, empty, empty.

Alluka does not cry.

Nanika loves Killua, even though she misses him.

She doesn't know why he left. All she knows is that Alluka is very, very sad. Nanika can't be angry at Killua though, because Nanika is sad that he's gone too. There isn't any anger to her sorrow, only hope that Killua will remember her soon.

Alluka loves Killua, because he came back.

Because she hopes, and hopes, and dreams that one day the door will open and Killua will come back to her, and they'll play and have fun like nothing had changed at all. She wanted it so much it hurt. She wanted Killua to come back and pat her on the head, and call Nanika a good girl, because he was the only one in the whole world who could do that for her.

And then, one day, that's what happens.

The door opens, and Killua is there.

"Onii-chan!" Alluka cries, because there's no way it could be true, but it is. She knew he would come back to her, she believed it, but the small tug of doubt pulled for so long she forgot what it was like not to have it there.

Killua makes a sad smile. "Alluka."

She launches herself at him, hugging him around the shoulders, because he's back, he's here for them, and she missed him so, so much. He hesitates, but he hugs her back, tightly but carefully, because Alluka's big brother is strong and he's always careful not to use all of his strength.

"I'm- I'm sorry, Alluka," he says, voice breaking. "I'm sorry for leaving you here all alone."

"It's okay," she chirps, nuzzling his shoulder. "I'm glad you're here!"

Then everything is made completely and totally all better. Killua plays with Alluka, and when she points her finger at him and goes 'bang' he makes the same funny noises and falls over, and when she says 'wake up,' he pops his head up in the way that always made her giggle.

They play shiritori, too, and that's fun, even though she's pretty sure Killua is going easy on her. Or maybe that's part of why it's so fun. Killua lets her win because he loves her, and that's much better than just plain old winning.

She leans her head on his shoulder blissfully. "Nii-chan, pat me, pat me!" she begs.

Killua smiles at her. He pulls her close and strokes her hair. Alluka hugs him tightly.

She's surprised when he picks her up, but she doesn't struggle. Alluka trusts her big brother. Killua always protected her. Killua came back for her. Killua loves her as much as she loves him.

"Oyaji," Killua says, and his voice is very hard. "Open the door."

Father is on the intercom. "I can't," comes the muffled order. "Make the wish right here. I won't allow the two of you to go outside."

Alluka is confused. Did Onii-chan need a wish? Is that why he came back? But why didn't he just say a command to Nanika right away?

"As expected," Killua says. "We really are father and son."

The intercom is silent.

Killua continues. "You called her 'Something from another place', didn't you? To be honest, when her eyes turn black I call her 'Something'- Nanika- as well. But we're leaving now whether you like it or not."

There is no response.

"Nanika," Killua says, and his voice is deadly serious.

Alluka closes her eyes. Nanika opens them.

"I'll pay the price myself," Killua promises, and there is an edge to his voice. "Nanika, if we aren't able to leave this mountain together within thirty minutes, kill Mother."

There is no surprise. Nanika doesn't think of killing as wrong in the same way that most people do. That would probably be true even if Alluka wasn't born to a family of assassins. All that matters to Nanika is the wish, and the person asking for it.

"If we are able to leave together, give me a kiss on the cheek. Got it?"

"Aye," Nanika says.

For Killua, she would do anything.

Alluka loves Killua because he is kind.

It took a long time for her to learn to recognize kindness, and even longer to understand it. Kindness is not a value her family promotes. Kindness is something Illumi-nii has accused Killua of for a long time, with a note of disappointment in his voice, as though he'd expected Killua to be able to extinguish any wayward sparks of that unwanted trait.

Gradually, though, she'd realized that if Illumi-nii said something was bad, chances were that it was actually good. After all, Killua was the best big brother in the world, and if he had kindness, that meant kindness was a good thing.

"Brother?" Alluka asks when she wakes up. "Where are we?"

"The hospital," Killua says. He has on the face he only uses for her, which is very gentle and smiling, but there's more hidden behind it- fear and sorrow and guilt.

"Why?" she asks curiously.

"My friend is here," Killua says in a low voice. "Sick in bed. I want to… I want to make him feel better again."

Alluka feels her hopes fall a little. Of course. That was why Killua came for her. It wasn't to whisk her away so they could live together forever. It was because he needed Nanika.

"So I have to turn into Nanika again?" she asks unhappily. "I don't want to. I want to stay here with you."

Killua shakes his head. "Don't worry. Remember what I told you? No matter what, from here on out, we'll always be together forever."

Alluka bites her lip.

"Please, Alluka," Killua says, and his voice is uneven. "It's my fault he's hurt. I'd fix him if I could, but I can't. No one in the world can help him except for you and Nanika."

Friends are also something Illumi-nii dislikes.

"Okay," she says at last.

"Nanika," Killua says, softly, desperately.

Nanika opens her eyes.

He guides her hands through the curtain and she touches burned, withered skin. It's the rattle of a human being struggling desperately to keep living inside a body that doesn't seem to want to live anymore. The air smells like rotting flesh. Killua doesn't seem to notice.

"Nanika," Killua says. "Heal Gon."

"Aye," says Nanika.

Alluka and Nanika both love Killua, because he's keeping his promise.

"Sorry, Gon," Killua says to the bright-eyed boy who is Killua's friend. "I'd love to go with you. But Alluka and I are going to be having a lot of fun on our own."

Gon nods, and he seems to understand. "Yeah, I know. I'll miss you."

"I'll see you again someday, okay?" Killua asks.

Alluka sees how hard this farewell is for him. She sees how hard it is, and she sees how much he loves her and Nanika. And because of that, Alluka is the happiest girl in the world. She's sad for Killua separating from his friend, but she loves him even more for that.

He promised they'd be together.

And they will be.