It's like trying to tame wildfire.

It's not that she doesn't understand. She is as sharp as a freshly honed spear-point, clever and downright witty when she wishes to be. She is my sister, after all.

Nor does she act in defiance to my wishes. She listens attentively every time I tell her how imperative it is that she control her powers, how our situation is precarious as it is, and though we can vanquish any mob no matter how many scythes and pitchforks they may wield, it will make life in our current location unbearably boring. I tell her we cannot feed on what little population remains after she unleashes her powers. I tell her that though like gnats they may be, a lady doesn't kill humans indiscriminately. She nods every time, she says she understands, she says she couldn't help it this once, she says she will do her best from now on.

Her smile is as radiant as the sun must be. And for a while, things calm down in anticipation of the next inevitable storm.

It is growing tiresome.

I will never know why she is unhinged as she is, whether it was some individual incident, either one we experienced together or something she never spoke of, or merely all our ordeals between the time we were first cast out and when I re-established myself as the mistress of my own fortune slowly grinding down her sanity.

Regardless, I know there is no coming back. She has always been a moody and fickle child, even before her mind fractured. And so I will tolerate it, the ill-fated massacres and inevitable relocations we have to make in their wake. For the time being, it still keeps things from growing too stale, and once it doesn't...

Even then, she is my dear sister. My only blood. Bound to me till the end of the world.

Then, one day, I almost lose my eye.

I excel at strength rather than speed, but I see the attack coming and move in time to prevent the blade from entering my eye. It strikes my cheek instead, cutting a wide gash all the way across my face, grazing bone.

The scalding flames from the blade are already sealing the wound shut as I fall on my knees.

Before I utter a word, my newest servant is before me, shielding me from future attacks. She is fully armed, the silver knives gleaming in candlelight.

The weapons prove unnecessary. The flaming sword has already retracted to its wand form, and clatters to the ground as Flandre's legs give way, the first of many tears to come rolling down her face.

The trickle turns into a torrent. She is so sorry. She didn't mean to hurt me, she just really wanted that second slice of pie, I could have it if I wanted it, if it would make me forgive her. Can I please say something, anything, even if it's just to yell at her?

Her finger scrapes at the floor as she weeps. Her weapon looks so harmless lying discarded by her side, like a toy.

Two thoughts cross my mind. The first is how very much I love my little sister, who is so sweet, so earnest, so genuine and passionate about all things. How clearly she loves me too, how readily she seeks my hand as my servant steps out of the way and embraces me. How she was my only blood.

The other is just how easily, had she used her powers instead of her sword, she could have annihilated me before I so much as blinked.

"You must do something about her," says Patchouli without raising her eyes from her book.

I look up from my tea. Though the library is mine, ever since I invited Patchouli to join my household she has been very insistent I keep all liquids at least five feet away from all books. Hence, there's a gap between our respective seats long enough that I'm not certain I heard her correctly.

"Flandre is a very sweet girl, of course," she continues, confirming my hearing is as flawless as ever. "But with things going as they are now, it's only a matter of time until she does something irreversible. Humans are one thing, but some of your maids have had close calls, and of course..."

The silence hangs between us. This is not a conversation I wish to have, but at the same time, I'm glad to hear someone voice what has been circling my thoughts for a long time now.

I set my teacup down. "What's your counsel, then?"

She sets the book aside and comes to join me by the tea service. Sakuya appears without the need to call and pours her a cup to her exact preference.

She nods at her in acknowledgement and waits for her to leave before continuing. "You don't need my counsel to know what the most merciful course of action would be."

Now, Patchouli is my dearest and only friend. Patchouli is one of the very few people I have ever trusted. Patchouli has never given me ill advice, and has stood stalwartly at my side when I needed aid the most. I have invited Patchouli to enjoy my protection indefinitely. I love Patchouli.

That is why I don't summon Gungnir and pierce her heart right here and now.

"She is my only blood," I reply quietly, knowing it will be enough to kill this line of thought.

"I thought you might say that." She helps herself to a pastry. "If you won't do that, but can't allow her to run amok any longer..." She pauses to take a bite, then delicately wipes the excess cream off her lips. "Then you must confine her powers."

I frown. "You mean, as in bind them?"

"Something like that. I have studied some rituals which can be used to suppress powers such as hers, but none potent enough to subdue her strength." Patchouli's ever-tired eyes flit towards my face. "I can do more research into them if you'd like."

"Thank you." Already, we both know such research is likely to prove fruitless. But then, if my sister's power cannot be bound...

"It's for her sake, too," Patchouli says after a long pause. "Do you remember how distraught she was that time she killed the raven that came to her window?"

All too well. Her howls of despair had rang in my ears for weeks.

I gaze at my tea. The pallid surface reflects my visions of the future back to me.

"How should I do it?" I finally say.

Patchouli has a distant look in her eye. "Customarily, troublemakers are sealed beneath the earth."

My sister, trapped amidst maggots and worms and decaying bones? I shake my head. "No. Not beneath the earth."

She shrugs. "A basement will do."

Her hand feels so slight in mine as I lead her to her new home.

She says nothing, and if not for her sharp, alert eyes carefully taking in everything on the way down, I'd have suspected she isn't aware of what's happening. But, oh, she's aware. Behind her eyes, past the unease, past the barely contained anger, lies a kernel of resignation I don't recall ever witnessing in her before. That is likely what makes her clutch my hand in turn and follow me without murmur.

It is almost as if she can see the future laid out before us as clearly as I do.

I let go of her as I open the door. Everything is fully prepared and has been since the moment I gave the order. My most prized servant is nothing if not deadly efficient.

"Here we are," I say, my voice as dignified as ever. Certainly it doesn't tremble.

She nods, a tiny, jerky gesture, and steps forward. She hesitates at the doorstep, turns, and proffers her wand. "Don't you want my sword?"

"What would you have me do with it?"

"Lock it up somewhere." The implied like me hangs in the air. "Like in the story where the hero has to find a magic sword before he can kill the dragon."

She has forgotten the details — the hero forged the blade himself — but I remember the tears she shed when she first heard the story and the dragon breathed its final breath and place my hand over hers. "Keep it." Parting Flandre from her most prized possession is a cruelty too far. "I may have to defend the mansion once we relocate. It's unlikely you'll see combat, but I'll feel better knowing you're armed."

Like she can't destroy any foe foolish enough to cross her path by blinking.

My words do nothing to dispel the unease from her face, but she clutches the wand close to her chest.

"Can I come see the stars sometimes?"

Her words are so indistinct it takes me a moment to make sense of them, after which I nod. "Of course. And the full moon." Every moment, I expect genuine resistance. Even if she understands what's at stake, I know better than anyone that her self-control only extends so far. "Do you have any requests for tea?" I continue as if it were any other peaceful day.

She shakes her head. I make a mental note to order her favourites regardless.

With that, there is nothing more to add. I wait to see if she takes the hint without my command.

She takes a shuffling step forward, then halts. Perhaps this must end in bloodshed after all.

But no. She raised her eyes towards me, with a curious mixture of childish innocence and the wisdom of her years. The latter gives me pause, even more than the accident had. I had thought that wisdom forever lost.

"Will you forgive me?"

It takes me a moment to realise she spoke, not I.

"For what?" I ask.

Her voice is barely a whisper. "For when everything burns."

Our eyes meet, and we hold the gaze for a long time. Already, I see the fires she speaks of kindling, reflected in her pupils.

Without thinking, I do something I haven't done in decades. I step forward, raise my arms, and embrace her.

She gives a shudder, like she has forgotten what the gesture means, then responds in kind, holding her palms close to the base of my wings. She leans her head against my shoulder.

My dear sister. My only blood. Bound to me till the end of the world.

And if the Fates will have it, my executioner.

A/N: With special thanks to Gravity Saix.