With every death, the unearthly wails of the invading army grow louder.

The gates of the castle explode with a mighty crash. The walls shake and the smell of smoke grows ever thicker.

The demons are within the keep now, the last remaining defenders falling like dust in a sawmill. A fight echoes down the corridor towards Lily's room, the clash of steel on steel, mocking laughter, thundering bolts of magic-

-a puddle of blood seeping under the door.

A pause, unnatural stillness washing out the sounds for a brief moment.

Then, a brisk knock-knock at the door, like a housewife calling on her neighbor for a teatime visit.

Her mother would tell her to use the knife now. 

Lily doesn't. Perhaps she isn't an obedient child after all.

Perhaps, instead, she is the kind of child who identified the possible entrances as soon as she was locked within, and hid in the best place for an ambush.

Lily remains very, very still, and very, very quiet, her eyes narrowed and breath nearly held, her hand gripping the knife's hilt hard enough to hurt.

She does not open the door.

The door opens itself. For a definition of open that admits disintegration. Through the space it formerly occupied comes flying an armored figure which hits the far wall hard enough to break bones. From the way the body puddles down onto the floor, it is assuredly dead. (The helmet rolls off. The face is a bloody wreck, but intact enough that Lily can identify it as her eldest brother.)

Then into the room steps the Demon Lord, Queen of the Dark, Mistress of Night. She has to duck slightly to clear the doorframe. Her armor is ebon, segmented plates overlapping like the scales of some great dragon, raising sharp serrated edges into the air with each flex of her joints. A cloak of shadow trails behind her, sucking in the light. Beneath the hood sits a bone-white disc, the only spot of brightness in her attire. The oval-shaped mask is featureless, no openings for eyes or mouth, but dimpled and blurry with some sort of texturing that can't be made out at this distance.

She should be in the woman's blind spot - 

Lily surges forward, utterly quiet, knife aimed for the best gap she can reach. (A joint, probably. She knows joints are often weak.)

The knife pings off the hidden underlayer and then she's heaved up into the air by the back of her shirt and thrown against the wall and pinned there by a hand at her throat. (All of which happens in much less time than it takes to describe the action.)

Then the bone mask is in her face and from this close she can make out that the texturing on it is finely detailed carvings of human figures in various states of torture, dismemberment, and death, none bigger than half a fingernail.

"So," says a voice. It should be terrible, it should be fierce, it should make your ears bleed to hear it. It's an ordinary woman's voice, one that would be unremarkable paired with almost any face she knows. And yet. All those shoulds are inextricably called up. "The final scion of the Vale reveals herself to me. I should have saved your mother to show her how casually you disregard her final wishes, child."

Her knife goes for the tiny gap between the mask and the chin. 

The blade snaps in half and the hilt is summarily knocked out of her hand.

"Child, I am so covered in reinforcements that you could not hurt me with a sledgehammer." The mask tilts, consideringly. "Not that you could lift a sledgehammer, I suppose. Though I do believe you would try."

If her family is dead - if her entire family is dead and she's the last scion - then she's the rightful ruler of this holding - 

She's going to try curling in half and kicking both the woman's armpits - one advantage of being so much smaller than her opponent.

- And at the same time, she's going to reach for the ley lines converging under the castle, feeding into the wards, and yank. 

She's pretty sure this will either fill her with tremendous power or blow the castle up. Either way, it's a weapon. 

For her troubles, she gets stubbed toes, a sudden dizzy spell, a muffled thump that shakes the foundations, and a tap on the forehead and the sudden icy shock of an antimagic ward.

"Clever little thing," the Demon Lord says. At the sound of further collapses in the distance, she cocks her head to listen. "That will be the west wing," she says when the noise subsides. "I dare say you've just killed yourself at least a score of my demons. Your hatred has potential, child."

She bares her teeth. "I'll kill more."

"Would you kill me if you could?"

"Yes."

"Good." Soft laugh. "Very good. You are worthy, child. I will train you, if you hold on to that hate."

"Why?"

"So that one day, I can kill you."

"Why not kill me now?"

"So that you'll have a fighting chance."

"I might kill you, then."

"You will try."

"More than that."

"Then it is a promise, child." The Demon Lord releases Lily, letting her fall to the floor.

She tries to land on her feet, but stumbles. (She tries not to look at her dead brother's face, but can't look away - )

Lily breathes heavily as she forces herself to steady feet, forces a stern gaze towards the Demon Queen's mask. (She's still shaking a tiny bit in the aftermath, still holding back tears and unable to control her blotchy cheeks.)

"Will you spare any survivors of my people?" she asks, even though she knows in her aching chest that it's pointless. "Since I am to be your student."

"The kingdom always needs more workers," she agrees. "They will suffer if you cause undue trouble."

Her held breath rushes out of her, and she tries to hide her relief. "Understood."

"Where are we going?"