Setting: Post-Mass Effect 3.

A/N: Written for the Halloween competition at Aria's Afterlife. This was inspired by the short story "Knock" by Frederic Brown, which goes: The last man on Earth sat alone in a room. There was a knock on the door. But in this fic, the last asari in one region of Thessia stands alone in a room. Only, she doesn't.

x-x-x-x-x

Tick, tick, tick…

I can feel the clock.

But as the last one here…

Do I hear a knock?

x-x-x-x-x

The quaking ground stilled hours ago, the final screams having faded to episodic memory. Aeian moved for the first time in a long while, a subtle shift of her foot on the slippery floor. Stiff muscles rebelled against the motion and started a dull throb, which her hazy mind barely registered. She blinked the dryness from her eyes, her heart pulsing to the rhythmic beat of the passing seconds.

Tick, tick, tick…

A trembling hand came up to press against her forehead, fingertips icy to her own skin. Her sight remained dark and blurry, and she waited for the vertigo to cease as she struggled to grasp her surroundings. Something heavy hung on her shoulders, so she shrugged out of it and heard the slight splash of a puddle when it fell. The sound jolted her out of her disorientation enough to bring some awareness back. Recollection came first, followed by sensory input.

Aeian remembered the transfer from Huerta Memorial Hospital and the eagerness of the nurses in sending her back to her homeworld. So this was Thessia, then. She stayed in her standing position and lifted her palms to rub her eyes, willing her retinas to clear faster. A metallic and rancid stench wafted into her nostrils when her sense of smell returned, and she promptly covered her nose, feeling her stomach lurch in response.

Tick, tick, tick…

Sheer willpower shut off the gag reflex. She kept her breathing shallow as she forced a step forward. Cold liquid seeped into the sole of her cloth slipper, and she dreaded the nature of its sticky consistency. Something sinister lingered in the air, almost tangible in its oppressive effect on her psyche. Faint light filtered in from the cracks of the ruined ceiling and dispelled the black edges of her vision, bringing the blue and violet walls into view. An enclosure, a room.

She tensed and froze. A room. This room. Why blue and violet? She remembered white. Painting job? No, an absurd thought. A different location? No. Once she had come in, she'd never left. She stared straight ahead, revulsion winding around her gut as everything came to a slow, horrific focus. Now she understood the color discrepancy of the walls.

They weren't painted blue, they were painted gore.

Chunks of asari flesh stuck to the surfaces amidst violet bloodstains. Even in the dimness, she could make out the dozens of corpses and dismembered limbs strewn all over the floor in a shallow sea of purple. Severed heads lay locked in expressions of terror and condemnation. Murder had claimed them in the grisliest ways. Medical robes outnumbered armor, datapads outnumbered firearms. The bodies revealed various stages of decomposition, most fresh from the kill, all hues of blue. The entire space reeked of monochromatic death.

But behind her frightened consciousness, her lurking subconscious found the colors quite pretty.

Tick, tick, tick…

What was that ticking noise?

Aeian wheezed out an anguished cry, her parched throat protesting the use of her vocal chords. Tears formed and spilled as she wept for the fallen. What had happened here? The galaxy at war, yes. The Reaper invasion, yes. Their subsequent destruction, yes. But why did so many of her people lie dead in this room?

Déjà vu struck, and she recalled the Tiptree carnage. She saw her friend Neaira, but in a twisted, bastardized version of herself. Neaira had turned and warped, commencing the massacre. The human colonists stood no chance against the banshee and the army of husks. The result was the same: widespread loss of life. Only, red and not blue, for humans bled scarlet. Aeian still ached at the memory of her useless role. Something said in her head, "Better you than I." So she left them to die. Not as if she'd killed them all.

She'd killed them all.

"No," Aeian rasped, nails raking down the sides of her face. "It wasn't my fault."

So then why this karma? This graveyard room? She scanned her surroundings again and felt her heart sink further. Reapers didn't cause these deaths; someone killed them and spared her.

She swallowed a gulp of foul air, no longer wanting to think. Yet the images came unbidden and swarmed her mental eye. Hilary's smile drifted past, sweet and pure… followed by her terror and screams right before Aeian was forced to silence her.

Aeian silenced many people.

She sloshed a few steps toward the left when her balance wavered, stumbling over a pair of detached legs before catching herself on a nearby counter. Her knees went weak as she uttered a sound of denial. She'd silenced them because she had no other choice. The return to the overrun Tiptree farm exposed them to scores of indoctrinated people. So in order to flee with the needed radio, would one not carve a bloody path to ensure one's survival?

…Would one not enjoy the rush of the slaughter even a little bit?

Tick, tick, tick…

Aeian sobbed, guilt rising anew as she cursed her own actions for the pictures they seared into her skull. She had escaped with her life, but didn't come out unscathed. Post-traumatic stress disorder, the doctors had called it. The survivor guilt complex consumed her, left her less than she was, left her unstable enough to warrant full-time therapy. From Huerta on the Citadel to this place on Thessia, psychologists did what they could.

But that still begged the question… what happened in here? Medical staff and soldiers, torn limb from limb and blasted apart. Who even held the answers if she was the last one alive? Her eyes flickered to the broken door. Actually, instead of lingering to ponder the piles of cadavers, why not just leave? She straightened and glanced down to ensure a proper state of dress before venturing out. And when the rays of Thessia's setting sun passed over her through the room's fractures, time screeched to a terrible halt.

The hands of the culprit were none other than her own. Violet blood stained both her attire and her skin, the evidence clear in the slight singe to her palms from overuse of biotic attacks. The echoes of voices screaming her name worked their way to the forefront of her mind, eliminating any doubt of her responsibility in this.

She was the one to paint this room blue and violet?

Her brain attempted to justify it at once. Perhaps she'd been defending herself? A desperate defense, an unfortunate result. However, a nagging feeling inside her insisted on something else.

Aeian's pulse raced to an audible thunder as she remembered initiating each assault. Over the course of days, her body acted without permission. Everything she was, everything she stood for, retreated to the recesses of her consciousness when something else had seized the reigns. A phenomenon called "ghost in the machine." And why did she recognize that term?

When her mental control broke, the insatiable blood thirst had set in. She'd been powerless against herself. First came the medical staff, then the soldiers who should have been out on the frontlines defending their planet from the true enemy.

She paused. The Reapers. They had to be the cause for her mind-body dualism.

Indoctrination.

What other explanation was there?

Knock.

What was that?

Aeian glanced toward each entrance around her, but saw nothing to make the noise. She returned to bracing herself on the counter, still rationalizing, still vindicating. She'd been indoctrinated, she was sure. Why else had the Reapers allowed her to live? She had proven a useful tool, killing her fellow asari without resisting the task.

But why her? She chanced a look over her shoulder and then tore her gaze away from her victims, lamenting to the goddess. Why her, when she already carried the burden of blame? Was her will so weak that those machines saw her as the perfect target?

Knock.

The second instance of the sound startled her, and she spun to face the door. Nothing there. A new wave of apprehension gripped her abdomen. She was alone… wasn't she? Even after hours of standing in one spot, paralyzed in a haze, she would have noticed if another living being still remained in the area.

But then… that provoked another question. If the Reapers had been destroyed in that flash of red light hours ago, why didn't the indoctrination wear off until now?

Aeian furrowed her brow, bewildered. She both desired and feared the answer. Maybe the Reapers survived. No, that wasn't right. She remembered people running around the building announcing the galaxy's victory thanks to some MIA Alliance commander. But then…

The deaths in this room hadn't stopped after that.

The Reapers were supposedly annihilated, yet she'd continued on as their avatar, slaying others left and right under her indoctrinated state.

Unless… it wasn't indoctrination.

Knock.

What was that knocking?!

Aeian grabbed a glass and flung it at the opposite wall, watching it shatter and land on the gruesome floor. First ticking, then knocking. Where were these noises coming from?

She stood alone in a room with the dead, a room with no working technology, and still she heard the incessant—

Tick, tick, tick…

Yes, that!

Aeian clawed at her scalp, issuing a frustrated scream. She should leave this place. Now. Before—

Tick, tick, tick…

Enough.

She pushed herself from the counter and made to stagger out the door.

A glimpse to her right stopped her.

The item she had shrugged off earlier lay in a crumpled heap on top of a torso. Realization flooded in with sobering coldness. She identified it at once.

A straightjacket.

This room wasn't in a mere hospital. It was a cell in a mental institution. Her transfer request from Huerta had been granted after she'd snapped and murdered half her assigned staff. Her punishment and sentence dictated solitary confinement. But even when she'd spent days by herself here wrapped in that straightjacket, she hadn't been alone.

Even now, as the only one drawing breath in this room, she wasn't alone.

Tick, tick, tick…

Aeian's expression went blank as the haziness slowly crept into her vision again.

She would never be alone because they echoed in her head. Past victims or personal demons, the difference mattered little. They took presence inside her, pulling her strings like a marionette more than the Reapers ever could. But she always distanced herself, proclaiming it wasn't the "real Aeian" committing these crimes. The outcome was dualism.

"Ghost in the machine" had been the term the doctors used to describe it.

PTSD wasn't the cause, but the trigger for the darkness. All along, it had resided within her, driving the urges, the thrill of the game. Also…

Not tick, but tic.

Tic, tic, tic…

A tic that strikes.

A tic that kills.

No wonder the Reapers had let her be. She'd been doing their work for them without even knowing. As her eyes went black, she reached for a discarded Carnifex. A perverse sense of euphoria accompanied her descent, with the major lobes of her brain shutting down and yielding to the whispering compulsion.

She had made it through the Reaper War, but the countdown had reached its end. All this time, she'd been a ticking clock, answering to an inner time limit, with one more victim to take.

The barrel of the Carnifex pressed against her temple.

Tick, tick, tick…

I feel the clock.

Not hear, not see.

I FEEL it knock.

x-x-x-x-x

A/N: I realize Aeian had an ambiguous fate on the Citadel (if Shepard didn't authorize her to carry a firearm), but I'm pulling the creative license card. Also, I know I slipped into more passive voice at the end there. I'll have to figure out how to restructure those sentences into active voice, but until then, this is it. Thanks for reading, and I'd appreciate any feedback!