He starts with nothing.
That's what he'd been advised, lectured by the hands that bundled him into Mist-child rags and dropped him stumbling onto the battlefield. Be nothing, he was ordered. Be empty.
Threats in the form of youth are in abundance throughout the Countries. Konoha wouldn't be the first village to be surprised by an explosive packed in the form of a babe, a fully-trained assassin tucked up in swaddling linens. A boy who dressed in full-equipment wouldn't look like an innocent to the Leaf Villagers come pelting through the storm. No. He would be perceived as a danger. Alive and on the battleground of snowy hills--he would be recognized as a mystery, and mysteries kill.
So it is castaway clothes Kabuto bears and little more, hand-me-downs from strangers he's never met. Those hands that abandoned him to chance also left no weapons on the field, no way to defend himself even by honest mistake.
No protection, no defense. Kabuto shivers in the snow, an open-wound vulnerability begging at the charity of Konoha's forces. Hoping to be found. Surrounded by ice crawling into his too-loose shirt collar and seeping into his overlarge sandals, slogging towards the dim sounds of death as his only compass.
He paws pale hair out of his face. Picks illusionary forms from out the blizzard, and traces the noise of screams.
A clean, blank slate,he was told. Be completely white.
That isn't hard for him to do while lost in the snow. He lets it fill him up as he walks, in his clothes and in his mind, until at last when the winds break open to reveal the bodies of the fallen, Kabuto doesn't even flinch.
The next time he experiences white as more than commonplace object is two months later, in his father's study.
The colors of the Yakushi residence are painted with an eye out for soothing tones, choices made with the same clinical relaxation in mind as the furnishings of waiting rooms. Medics bring their work home with them as easily as any other profession. Kabuto's mother had requested specific forms of beige, tan and ivory to spruce up the house with, so neutral that the Yakushis could have seen patients in their kitchen with the same professional aplomb.
White is nothing special in the Yakushi house. White allows for bleached clothing and sterilization. Kabuto has become accustomed to white as a comfortable standard by the time he wanders into his father's study one afternoon, and sees a rainbow split wide open in dissection on the wall.
He stands in the doorway, fixed by his discovery. At eight he is still uncertain enough in the Village that he'd picked up the bad habit of shoving his fist to his mouth whenever he is nervous, and the gesture happens again now, fingers jamming themselves against his lips.
Page whisper. Kabuto's father is seated at the desk, going over one of his diagnostic manuals. Sunlight is pouring through one of the windows and pooling over the papers and books, over the bones of the instructional skeletons standing in the corner and finally meeting up with the prism.
"Ah, Kabuto." His father's voice is salted caramel in a room of afternoon honey. He flips another page, marks it with a penciled loop. "Did you need something?"
Kabuto's reply is a whisper hushed, so as not to break the sunbeams. "Dad."
The word is strange for him to use when he is thinking of any other color than white. For all her medical skills, his adopted mother hasn't been able to conceive. Whether that spurred her husband to take in the foundling from the field or not, Kabuto has no evidence for or against.
If they see the blank slate in him that they could shape into their child in truth, Kabuto doesn't know. If it blinds them to all other suspicions of his origins, then their soft hearts fall in his favor, and he can't complain. Their compassion gives him luxury to move. It allows him to be a newcomer in a Village which has outlasted its enemies and made a number of them along the way.
Kabuto is a cuckoo child. His feathers have not yet grown in past their pale downiness. There are no other nestlings for him to kick out in the meantime, thankfully, so they remain pristine.
He thinks of white when he is nervous as a child. It makes some things easier to say.
His father looks up once more from his book when he realizes that the boy has not moved; following Kabuto's fixed gaze, the man breaks into a chuckle. "So you like the paperweight, do you? I keep it because it's just like anatomy." The doctor hefts the manual aside, setting down his pencil to tap the glass pyramid with a finger. "People are made up of hundreds of working parts inside that combine to give you the picture on the surface. You look at a sunbeam and see only the basic light, but when you split it apart, you see that it's much more complex than that."
Kabuto's father continues to speak, unaware of how the child is edging in from the doorway and sideways against the wall with the same wariness as if he expected the colors themselves to leap out of the rainbow, and devour him.
"Part of our work as doctors is to figure out what might be inside," the man jabs a finger at the prism, "by studying the outside first and then progressing deeper."
"So white is a lie," Kabuto observes, around the knuckle of his thumb.
By now he has crept halfway towards his father's desk, methodically following the corners of the room by sidesteps, back against the wall. He bumps the books with his spine as he leans into their support. The texts are deep browns and reds and greys, but Kabuto knows the pages inside are all pale underneath the print.
"Yes and no." His father's sigh shows that he has not yet thought of this particular descriptive for the prism, but now that he has been presented with the symptoms, he will address them each in order. "White is made up of all these colors, but it's also itself at the same time. Only when it's a beam of light does it have these things, you know. If you try to take the colors in nature and make white out of them, all you get is black. I think you've discovered that already with your painting set, much to your mother's chagrin," the man smiles, paternal conspiracy for his adopted son.
Kabuto takes his hand away from his mouth, wipes it on the corner of his shirt. "Yes."
His father is already moving on in his lecture, propelled by his own instructional practice. "Just like you're more than your arm or your nose, so too is a person like a ray of light. But you can shine all the colors of light on a unified spot to make white again. You can't do that with a body. Since we haven't learned how to bring a person back to life from just mixing together their organs," he continues, turning the heavy weight of the prism in his hands, spiraling the rainbow across the wall, "we have to handle them as if they're paint. Do you understand, Kabuto?"
"I think so." The study air is musty, warm, and Kabuto doesn't need to feign the yawn. His mother had sent him to fetch his father for an early dinner, but the afternoon is just reaching its zenith, and eating doesn't seem half as attractive as sitting in a room of books and skeletons. Nor as horrifyingly interesting as staring at the colors exposed on the walls.
"White isn't a lie," his father concludes, turning back to his books. "It's just... easily overlooked sometimes. Like you, Kabuto," he adds, reaching over to ruffle the hair of the boy, tousling the cuckoo fluff. "The kids in your class aren't bothering you still, are they?"
"No," Kabuto says.
Which is true enough, once the words are passed through a filter, gutted to shine like rainbows.