His obsession was founded hundreds of years ago, in the golden era that preceded the Great Exodus. He remembered it fondly, that moment; the first time he had seen her, the first time he had touched her.

She had arrived in his office as one of many youthful 'bots recovering from the scrapes and dents of a minor joy-riding accident. He was often in demand for such work, in those days, as his extensive medical knowledge came coupled with a refined sense of aesthetics. No one else in the region had earned his reputation: "a master of chassis repair," he was called, "a true artist," and yet he had not known art at all until his optics scanned the young fembot standing tense and uneasy in his med-lab.

No detail was forgotten. He could still recall the time and date. He had entered the med-lab with data charts in hand, reviewing what basic information his aide had collected about the unknown patient. "I am Knock Out," he began, absent of tone. "Just that. I don't care for that 'doctor' nonsense, and – "

He glanced away from the chart to crack a half-hearted smile along with his half-hearted joke, and it felt as if lightning had struck his spark. The jolt was painful yet energizing. His circuitry felt overheated, and his optics refused all attempts to look away from the femme. "...half my aides just say 'hey, you!'" His voice sounded far-off and strange to him, and perhaps to her as well, for she reacted to his weak sense of humor by folding her arms across her chestplate, her optics looking away. He did not help matters any by laughing too loud.

Sleek. From the tips of her pointed toes to the fragile-seeming winglets portruding from her back, she was grace given form. Every lustrous curve of her chassis was crafted to entice. When she transferred her weight from her right leg to her left – such a small motion, so casual – his attention was riveted to the pleasing round sensuality of her shifting hips and flexing thighs. Strong cabling flowed in mirrored paths along each side of her long neck, coming together in a loose embrace that plunged beneath her metallic bosom, the ample feminine shape of which protected her spark-chamber. Her blue optics, tilted slightly upward at the outer corners, bore great intelligence and greater passion. Never before had he seen such female magnificence.

She was flawed, yes. She was no longer a sparkling, and so the childish pink-and-white of her paint job, though striking, did not suit her. He knew right away that she was overdue for independence, and that her parent-units had been sheltering her to an unwarranted degree. Her willowy body was designed for speed, elegance, and beauty, but she had been so thoroughly raised on strict mannerisms that she appeared stiff and stunted.

Only the absolute confidence which put steel in her purring voice implied she knew anything of her potential. "Arcee," she introduced herself, the name burning into his circuits at once, a scar which was fated to never quite heal. "Will this be...quick?"

"No, my dear," he'd responded, his voice soft but insistent. "I must examine you thoroughly..."

Then, she was his; at his command, she settled into his medical berth for the next hour while he conducted every test and diagnostic he could conceive. Scanners probed the fembot in long, slow sweeps, making bare any secret her body possessed. He memorized the sweet crescendo of quickening fans and vents, the sound filling his med-lab each time she grew anxious. He stroked healing polymer into her scratches himself, taking his time so as to savor the feel and shape of her frame beneath his fingers.

She did not resist him; why would she? He was the medic, and she his patient. Perhaps he should have felt ashamed at his behavior. He was taking advantage of his patient's trust.

Their conversation was at first as firmly polite as one could expect, yet as time wore on and her patience grew thin, he began to see glimpses of the fiery persona that lurked beneath her lady-like exterior.

"You should be more cautious," he urged her. "Such a lovely paint job shouldn't be put at needless risk."

"You don't need to lecture me, doc," she snapped back. Her tone startled him at first, and then he was smirking.

"Did I touch a nerve?" He had to laugh. She looked furious with him, though she said nothing else, retreating into a smoldering, sulky silence that kept a smile on his face for the duration of the exam.

He had not seen that sweet, angry expression again until the two crossed paths on the battlefield.

He recognized her at once despite the change of appearance. Her chassis was sharper somehow, cleaner, voluptuous curves traded up for a predatorial frame that was more suited to her role as scout leader. Gone was her original paint job, too; in place of innocent pink was a deep midnight blue highlighted by lines of gleaming gold and dusty rose, the thick and impressive armor plated in layers over gunmetal gray. Even her vehicular mode had been upgraded to a swift, sleek motorcycle form instead of the sportscar she had adopted as a sparkling.

She was racing along the outskirts of Decepticon territory when he pounced, driving hard into her side. The two-wheeler skipped across hard pavement several times before she unfolded and turned her tumble into a nimble backflip. The surprise he felt at recognizing the Autobot stayed his hand long enough for her to spring into action and burn rubber back to the rest of her patrol group, a delay that Breakdown immediately noticed and called out.

"Th' hell's wrong with you?" Breakdown's accusatory voice had no room for real concern, even though the two had been partnered since the war's inception. "You let her get away. She was an easy target..."

"I knew her," Knock Out grumbled. "Won't happen next time."

And so it did not.

He tracked her movements using every trick and technology at his disposal. Each time he intercepted her, he fought to kill her allies and claim her as his own, claiming "the Decepticon cause" as his excuse. He argued that as a scout and spy, Arcee would have access to valuable Autobot intelligence. She would have to plot her own movements in accordance with her faction's plans, and he meant to pry every detail from her screaming lips. Megatron liked the sound of that.

It was therefore his fault that she was taken by Airachnid. His arguments had been too effective. Megatron agreed with his logic, and dispatched his most lethal interrogator to claim the fembot.

Knock Out was forced to watch from the shadows while his prey was tormented and picked apart by another bot's hands. He longed to be part of the proceedings and to refresh his knowledge of her beautiful chassis. He craved to draw out her pleas and screams himself. He wanted to make her surrender to the Decepticon way, so that he could at last claim her as his own...completely.

He leaked Arcee's whereabouts to the Autobots and watched, triumphant, as Airachnid lost her favorite plaything.

At least Airachnid's work was not entirely in vain. She was reluctant to share her interrogation logs, but gave in when he drew Megatron into the argument – "Just give Knock Out what he wants and get out of my sight!" the Lord had commanded, seething with rage at having to mediate what he called "pure foolishness." From those logs, Knock Out culled every nuance and detail of Arcee's character and form, using the information to seed his next demented project.

He was an artist, they said, so he would give them art. Construction began immediately after he determined the proper alloy which comprised her chassis. Materials were easy enough to come by; the battlefield was so littered with Autobot and Decepticon pieces that he wanted for nothing. Some scraps were already suited to the task and did not require changes or improvements. Other components had to be worked over for years in order to be absolutely correct; his vanity did not permit anything short of perfection.

A long stretch of empty years interrupted his work. He traveled the galaxy with Breakdown, drifting from energon signal to energon signal like worker bees in a field of endless flowers. It was coincidence that drew them to Earth. It was coincidence that the Autobots and Decepticons had carried their war to that planet. It was coincidence that she was there, waiting for him, alive and still fighting despite the millions like her who hadn't made it. Though he was duty-bound to obey Starscream's summons, he was breathless with anticipation at seeing Arcee again, and their first clash outside the human museum reignited his obsession. Their war resumed, and so did the construction, the half-formed chassis having survived Knock-Out's journey through the stars.

Time had hardened the two-wheeler into a goddess of battle. Watching her fight was to witness living art; he had never before seen anything half so glorious! He exulted in her triumph, and despaired to see her fail, even as he added her advancements and flaws to his older schematics. Scraps from shattered Decepticons fed the growing form, and carefully-stolen shreds of energon gave it life. When the optics flickered for the first time, he thought his spark would burst with pride.

A near-complete replica, perfect to every exact detail...and with it, he would seal the final fate of the Autobots and finally take Arcee for his own.