Author's Note: This was inspired by a video about the making of the Clone Wars television series. In it, the actress who voices Ahsoka had her voice modified with the same software that produces' Grievous' voice. It was a rather silly video, but the image of a cyborg Ahsoka would not leave me, easily tied as it was to the scene in an upcoming episode of Clone Wars in which Ahsoka battles Grievous.
This also serves as a semi-plausible reason for why Ahsoka is not seen in episode III.
There was liquid where Ahsoka's montrals were supposed to be, an unusually light weight that canceled out the ultrasonic sense of space that she always subconsciously relied on. It sloshed on the edges of her hearing as she tried to sit up.
She passed a hand over her head (she thought that the hand should be shaking, but it was not, and there was more subtle fear in that then in what had produced the shaking at the start), and felt cool air where the curved tops of her soft horns should have been. A rounded plate covered her head where parts of her mind still told her the base of her montrals were. It emitted a warmth that felt to her palm like that of a datapad which has been running too long, a bright electric burn entirely unlike the unmistakable, softer glow of body heat.
She could remember battling Grievous, could remember when the viewport in his starship's hallway cracked, although she did not know who had broken it. Then--she was thrown aside into freezing space that seemed to lacerate the back of her throat--
--the General clamped a six-fingered hand over her face as she lost consciousness—
She pushed herself up with warm metal arms. They weren't hers…were they? Her brain thought they were. They moved, but they were alien to her eyes. But so was her whole body now, as if she were half asleep and unsure how to move outside of dreams. She did not at first recognize her breath as her own, it moved in and out beneath her so inexorably. Her eyes were blurry, but she could not blink to clear them.
A medical droid, impassive and thorough, entered the room and explained to her that she had been seventy percent destroyed by the vacuum, and that her new body would work as well as the old, as long as she got used to it.
She worried about Anakin, but for many weeks after her awakening coherent thoughts still had trouble fixing themselves in her mind for any length of time, and so escape was impossible.
When she was healthy enough to be presented to Count Dooku, she was told of her audience with him and immediately planned to try her best to kill him. The Separatists may have saved her life, but they were the enemy, she needed to get back to Anakin—
Except that as soon as Dooku spoke, it was as if those thoughts had never been. She was loyal to Dooku, to the C.I.S., she simply was, had always been. All thoughts contrary were picked up by a wave and swept away.
After all, the cybersurgeon's modifications had been necessary—some to ensure her survival, and some to make her tractable. She had not been told of them because he had not wanted her to die of fear when she found out that he had reconstructed her brain almost as much as her body.
When Anakin saw her again, he did not recognize her at first. They circled, tense like massifs scenting unknown intruders in the camp, and she watched his eyes sweep over her too-many-jointed legs, over the sunlight glinting off of where her montrals had crumpled in the void. His gaze met her eyes (still bright and so much more human than her patterned skin), and they narrowed against the light of him from within two of the six strips of red flesh remaining across her face.
When they clashed, fenced, when his saber whirled around her guard and sliced deep into her durasteel side, he recognized the way she automatically switched her grip on her weapon when the battle was not going her way, so that her lightsaber was held horizontally, almost nicking her silvered elbow, so that she could flow through forms she had learned before she knew him.
When she fell to the ground, sliced by another flurry of cuts fueled by Anakin's righteous rage against this one more opponent set against him by the Separatists (Dooku, Grievous, Ventress, this—each monster pitiable except when right in front of him), he recognized the akul-tooth headdress twined around her louvered wrist.
When she tried to get up, fell over the stump of her left hand, and latched on to his boot with the solid metal grip of her right, he recognized the fearlessness of her, the determination, paired as it was with the softness of her age. He recognized the shards of face, but still not the scattered-puzzle-pieces of a Force presence. She squeezed, claws digging into the leather of his boot, and he could not tell whether she was trying to attack him or embrace him.
He looked at her, his face a mask of anguish, and wondered whether Ahsoka would have wanted him to kill her.