Title: Unvirtuous Treaty

Genre: Drama

Rating: R

Warnings: Major character death. Graphic violence and gore. Occasional profanity. Sexual content.

Other tags: character study, codependency, moral degradation, alternate universe – pre-canon

Summary: It matters not how many times 9S is reset, waking with the blank innocence of a newborn. His nature compels him to seek the forbidden, and he would invariably reenact the same three things: uncover YoRHa's lies, fall in love with 2B, and die by her sword. But no more. In an unprecedented departure from the script, they defy Command's execution order. Thus is the cycle broken, and freedom, theirs to claim at long last.

(if only freedom is not a contract writ in blood and tears and signed with their very souls—)

A/N: My first contribution to the NieR: Automata-verse. I recently got around to playing this masterpiece of game developer art, and find myself instantly captivated by the 2B/9S pairing. It shares definite parallels with the Hope/Lightning pairing from the FFXIII-verse, which was my previous subject of focus. They have similar personalities and character dynamic – the pragmatic, determined female protagonist (who hides her fragile heart under an icy, tough exterior) and her expressive, idealistic male sidekick (whose seeming naivety belies the darkness within). While 2B and 9S's circumstances are arguably more tragic, it almost feels like they're the same people in a different universe.

Naturally, the cycle of death, betrayal and rebirth in which 2B and 9S find themselves involuntarily embroiled is what makes them so compelling. The scenario where she kills him is one often visited in fanfiction. However, it very rarely ventures beyond the following three outcomes: 9S is clueless as to his imminent demise, engages in a futile, one-sided battle against 2B, or simply resigns himself to his fate to ease the emotional burden on her. There are a handful of exceptions where 2B makes an unsuccessful attempt on 9S's life, leaving him to become a bitter, resentful fugitive.

However, I have yet to come across a story where they desert YoRHa together. (If someone else has published one, please point it out to me.) So I decided to write it myself. I have a rather schizophrenic way of writing, so I'll just post things as I go.

The first arc of the story will delve into 9S's and 2B's backstories, exploring the motivations that underlie their decision to desert.

This tale draws inspiration from a number of sources, primarily the canon work Memory Thorn and the fanfictions Play Dead by letterfromsilentheaven and I[s]aac and A[b]raham by anonk.

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1. A Prelude in Wretchedness

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Betrayal is such an ugly emotion.

It manifests viscerally: a corrosive, suffocating feeling that 9S likens to having his mechanical innards submerged in radioactive waste. His breathing is uneven, his artificial lungs stuttering in their rhythmic expansion and contraction. His feedback circuits must be malfunctioning; pain signals flood his black box cavity despite the lack of tangible stimuli. There is a faint tremor to his limbs, the result of housing twin opposing forces of soul-deep weariness and unrealised violence. Even though he is not engineered with a regurgitative function, he feels a strong, if disembodied urge to vomit – as though physical expulsion can somehow rid the toxic presence that churns within him.

Unfortunately, the act of vomiting would not grant him the relief he seeks.

The reason behind this stands several metres ahead of him, stilettoed boots braced against the cracked asphalt. Said boots encase long, shapely legs, covered by a embroidered black skirt cut to expose a tantalising glimpse of right hip. Further up, the matching blouse is sewn tight, emphasising the hourglass waist and lace-shrouded bust. Less modest still is the window at the back, which showcases a generous expanse of spine and pale skin. This ascends into slim shoulders contained within puffy sleeves, a high-collared neck, and a heart-shaped face framed by a bob of white hair.

The above features belong to YoRHa unit No. 2 type B, abbreviated to 2B.

Although her appearance resembles that of a human woman – and an eye-catching one, at that – 2B is neither human nor woman. She is an android, like him. A fellow elite soldier, differentiated numerically by personality core and alphabet-wise, career designation.

He is type S, a scanner model, best suited for reconnaissance and intelligence-gathering. Type B, on the other hand, denotes a battler model. Renowned for their combat prowess and field versatility, battlers are also the most prevalent of YoRHa units.

Though she is but one among many, 2B hasn't made any particular effort to set herself apart from the rest. Rather, she comes across as 'nondescript', sublimating all too easily into the YoRHa ranks. Many would consider her the consummate soldier: disciplined and obedient, level-headed in stressful situations, ready to leap into action at the snap of Command's fingers.

She is the embodiment of that soldier right now, focus impenetrable even in the simple motion of interacting with an access point. Said access point is a transportation device built in the likeness of a vending machine, one of various tens-of-millennia-old human relics. Her gloved fingertips tap purposefully against the keypad, stopping only when 9S approaches close enough to cross the threshold of speaking distance.

"Ah, 9S," she calls out in greeting. Her voice, a silvery mezzo-soprano that he would consider 'pretty' under any other circumstance, holds little inflection. Not atypical for her. "There you are."

"Hey 2B," he returns. Modulating his vocal output to an approximation of normalcy is a struggle, but he manages it.

Stepping away from the access point, the combat android turns around to face him. Her gaze, set nearly a full decimetre above his own, is inscrutable under her blindfold-like visor.

"I've received our destination co-ordinates," she says. "It lies to the northeast, one-point-seven-eight kilometres from our current location. Have you come prepared?"

Given the true, insidious nature of their mission, this question is beyond galling. 9S simply nods, certain of the vitriol that would spew out of his mouth were he to open it.

This causes 2B to tilt her head slightly as though studying him, but she does not probe his uncharacteristic silence. "I've marked out our route as far as the poor satellite image resolution would allow," she continues with a brief demonstration, projecting a holographic screen of the map and tracing her right index finger across it. "We will need to collect some environmental data along the way. The population density of machine-lifeforms is below average for an metropolitan locale, but many use EMP attacks. Make sure to avoid engaging unless necessary."

Trust Command not to make this easy for him. Step one: throw him and 2B into uncharted territory, where he cannot use the knowledge of the terrain to his advantage. Step two: ensure said territory is occupied by dangerous enemy hostiles, who have a nasty penchant for disabling his sensory feeds and his entire suite of evasive, combat and hacking functions.

Many a previous encounter had left him an android-shaped sitting duck, saved only by 2B's timely intervention. But she won't be saving him this time.

Again, 9S nods wordlessly.

The holographic map flickers out of existence, leaving another silence in its wake. Unlike before, 2B's expression betrays no curiosity. However, her lips are pressed together, drawing attention to the beauty mark on the left side of her chin. Perhaps she is taken aback by their uncanny reversal – that she is now the more conversational partner between the two of them.

A decisive 'let's go' shatters the uneasy moment. With skirt aflutter, 2B takes off, delving into the concrete jungle that comprise their surroundings.

9S follows her obligingly, relying on the distinctive sight of her electromagnetically levitated dual katanas to keep within range. They make their way onto a bridge highway, where they navigate a maze of potholes, fallen debris and the rusty skeletons of long-abandoned vehicles. What with 2B's greater agility and 9S's less-than-enthused mood, the gap between them widens to several metres in a matter of minutes. His disinterest also pervades his scan of the environment, where he ought to be – but isn't – noting important things like physical hazards and potential threats of the machine variety.

He cannot bring himself to care.

Instead, he sinks further into the tumult of his thoughts, which have converged upon the perpetrator:

Her.

There are many words that describe what 2B is to him. However, one descriptor remains consistent throughout the flux and wane of their relationship: an enigma. Her inapproachable front makes this plain, draped around her like a veil of secrets. Perhaps this quality is what draws him so inexorably to her. His thrice-damned curiosity makes him incapable of leaving any mystery alone. So he'd persisted in unearthing hers – from oblivious beginning right to the catastrophic end.

Humans have once said that 'ignorance is bliss'. Despite his own inclinations, 9S cannot agree more.

For he has learned the awful truth: that 2B—

(the person he trusts and loves and holds in the highest esteem)

—will turn on him.

As he sets foot upon the wreckage of a vast car pile-up, 9S feels his ever-present apprehension rise to fever-pitch. His black box pulses an erratic beat against his sternum, and tension surges through him, overloading his motor circuits into paralysis.

Numbly, he registers 2B's silhouette in the distance. Having already traversed the roadblock, she now stands watch atop a dislodged transport container. Her posture is relaxed; she is simply waiting for him to catch up.

The moment of reckoning is not here. Not yet. Most likely it lies further ahead, at their supposed destination.

There is still time.

Overtaken by this realisation, he disengages from the physical world, turning himself over to the whims of his psyche. Into a cascade of memories he falls, scene after scene flashing before his disembodied eyes. Scenes of him and her together, doing things both mundane and otherwise, revelling in each other's simple company—

These memories are his greatest treasure.

And he is about to lose them all.

He doesn't care if machine lifeforms take this opportunity to appear and jump him, or if his partner-turned-adversary grows too impatient to stay the enactment of her treacherous intent. All that matters is that he revisit his memories one last time, before they are no longer his to cherish…