There was not a soul alive aside from Sasori himself who knew anything of his past. Regardless, here it is, as best as it could be compiled.
-.-.-
Sasori had been born into a happy little family. He was an only child, his parents were very much in love, and his grandmother positively doted on him. He was a spoiled child, but not to the point where it would mar his personality. His life was very sheltered as well, but mostly, it was just happy.
His grandmother was a retired ninja, well-liked and respected by everyone. She occasionally advised the village council on matters concerning foreign relations, but otherwise lived a quiet life at home, taking care of Sasori when his parents went off on missions.
But one day, when he was just five, all of that changed. His parents were off on a mission again--he barely understood the concept, let alone the danger it posed to his world--and it was a day like any other when his grandmother came home crying. Sasori didn't understand it. He was just trying to color a picture for his mother when she returned, and his grandmother picking him up and hugging him so tightly that he could barely breathe kind of impeded that process. He just politely asked her to let go of him, because he really wanted to get done with this picture before his mother got home.
When his grandmother just kept crying, the young boy had the tact to ask her what was wrong.
Sasori never got quite a straight answer, but by the time he was six, he knew that his parents weren't ever coming back.
Around that time it was that he first claimed any sort of interest in the actual affairs of shinobi, and conspired to beg his grandmother to let him enter into the academy. She of course said no, and Sasori used the only weapon readily available to six-year-olds: pouting. He stayed cooped up in his room for nearly a week, sighing and moping around, before he got any sort of result.
His grandmother just took him aside and told him that he couldn't be a very good ninja without a signature jutsu, and taught him how to create and utilize puppets. He was smart enough to realize that this was also so he'd get his mind off of the fact that he was being raised by his grandmother, and not his parents, like other children. But he didn't really care about that. Yes, he missed his mother and father dearly, but a child's memory isn't the strongest, and already time was wearing down their features in his mind's eye. The only picture he had of them--besides the ones he'd drawn, of course--was when he was still an infant. He remembered that his mother had cut her hair sometime after that, but Sasori decided that he liked her better with longer hair. He liked long hair.
His skills grew exponentially, before and after he entered into the academy. He created puppets lifelike enough to pass as people.
That was when Sasori met the Sandaime Kazekage, for the first time, in person.
He was completely and utterly amazed. One might say enamored. Either way, it quickly became an obsession. Sasori couldn't figure out how the iron sand ability worked, how the Kazekage could control it. And of course the Kazekage wouldn't dare tell him. But Sasori wanted a puppet like that. He wanted one so very badly.
It had been an accident, mostly.
It was on a mission, in which his partner had died. It had been a somewhat pretty blonde girl, and he had suddenly been inspired.
It was on that day that Sasori made the first step to being the man he was today. First, he discovered art. His puppets were art, he'd just never consciously realized that before. And that art was immortal; it outlasted his partner, didn't it? His puppets wouldn't die, no matter how many times they got stabbed, or how old they got. They couldn't get sick or poisoned. They would never die. They were…eternal.
Secondly, he discovered what he could do to the human body.
He made his first human puppet on that day, out of the corpse of his recently deceased partner. It was a sloppy, messy job, since he couldn't drain all of the blood, and her wounds had made things difficult, but when he returned to Sunagakure with a new summoning scroll and informed the Kazekage that his partner's body had been lost on the mission, Sasori knew he had done something that no other person had ever attempted before.
When Sasori was staring at the blonde girl's puppet--it stared listlessly back--he was already formulating vague concepts of plans and half-baked ideas for another human puppet.
He was still thinking of the Sandaime Kazekage.
It took nearly a year, but with more experimenting, more human puppets, and more refining of his skills, Sasori had his puppet.
He had to do the process in a cave a few kilometers south of the village--while all of the villagers were in an uproar--but it was absolutely perfect. The Sandaime was dead, but his body, and his amazing iron sand, was still here. It was still alive. In a sense, anyway. The twelve-year-old hugged his new favorite puppet, ignoring what he'd been through to acquire it. And what he'd just been forced to give up.
He couldn't go back to the village, of course. He never could. Even if no one knew it was him, it wouldn't take long for someone to figure it out. And plus, how could he use his new, favorite weapon, where everyone in the whole village was looking for it?
So armed with nothing more than a mere half of his puppet collection and a red, conspicuously Suna uniform, Sasori left Sunagakure and wandered aimlessly out into the desert. If it had been during the day, he never would have gotten away, no matter how skilled he was. But the darkness--and a bit of luck--was on his side.
He had decided to stop at one of the towns on the southern border of the Land of Wind, early at dawn, to try to get some sleep and wash the blood off of himself. If he hadn't stopped there, more than likely he would have been captured by Suna ANBU.
And, of course, the first thing the young ninja did was go to the nearest bar and get completely drunk. He couldn't stop thinking about what he'd just done to their village leader, of all people, and Sasori only hoped he wouldn't have nightmares for the rest of his life. He was only slightly amused that the barkeeper sold him several drinks without even asking his age, though there was no way he looked old enough to be legal.
It was at that bar that Sasori first met Kakuzu.
The redhead sat bolt upright when the massive man sat down on the stool beside him. Sasori really couldn't help but stare at him, but the man didn't bat an eye in his direction. After the initial shock wore off, and since he didn't say anything, Sasori sullenly turned back to his drink.
Several alcoholic beverages later, Sasori could hardly sit up straight.
"Hey, kid." The ex-Suna-nin couldn't summon the energy or thought to reply to the man, despite the fact that he was towering over him by a few good feet. His head lolled limply to one side as this mysterious stranger put a hand on his shoulder, and gave him a none-too-gentle shake. "You forgot to wash the blood off of your fucking hands."
Sasori looked down at his hands. It was true. They were still splattered with blood.
"And you might want to get rid of that damn hitai-ate." Sasori didn't question how this man knew he needed to get rid of it. "In fact, I don't even see why you're getting drunk. You're going to have a hangover like hell tomorrow, and you can't run from hunter-nin if you can't get out of bed. You're an idiot, aren't you?"
Sasori looked up at this man with large, brown eyes, somewhat glassy from the alcohol in his system. "I'll kill you if you call me an idiot again." He was still sober enough to be proud that his voice hadn't slurred.
"What's your name, kid?"
"Sasori."
"Well, you're an idiot, Sasori. A little runt like you, wearing a bright red outfit, out on his own? I should kill you just on principle." The man leaned down, so that he was eye-level with the drunk Suna-nin.
Sasori stared at him, refusing to blink. "I'll kill you if you call me an idiot again," he repeated stubbornly. He reached down for the scrolls attached to his belt. Each one summoned a different puppet. With a shiver of excitement running down his spine, Sasori wondered how the Sandaime would fare in actual battle…He hadn't had more time that to test out whether or not the iron sand worked before he had to flee. Luckily, it had. This mysterious man had no idea who he was going to be going up against.
He laughed. It wasn't a pleasant laugh. "You have no idea who I am, do you? The name is Kakuzu." Sasori probably should have been alarmed when a good portion of the bar stood up and left at that point. "I'm a bounty hunter, but since you're just a stupid little runt, I don't feel the need to waste energy on killing you. Maybe if you grew up a bit and killed a few high-class people, I'll come back to visit you one day. Idiot."
Sasori threw a punch, but his fist was caught easily. He nearly growled. "Sh-Shut up! You're the idiot and I've already killed the Kazekage!!"
The rest of the bar promptly cleared out. No one liked to be caught in a ninja fight.
Kakuzu went very still, and very quiet. He was staring down at the drunken Sasori with those strange, inverted eyes of his. Sasori stared defiantly back, holding out his newest scroll already. He couldn't remember when he'd got that out, but at least it was at the ready now. Just a bite of the thumb, and he'd have his beloved Sandaime out and he would kill whoever this stupid Kakuzu guy was. It wasn't like he'd ever heard of him, with the sheltered life he'd led until then.
"…So little red riding hood has a few skills, huh?" Kakuzu tilted his head to one side, laughing again. Sasori bristled at the nickname.
"I'm not--"
"No, I guess you're not. You don't look feminine enough. But you've got the red outfit down."
-.-.-
It was several years later when Sasori saw Kakuzu again. This time, the bounty hunter had tracked him down. Sasori could say that he was almost expecting him; he'd accomplished quite a bit in the way of murdering people since they last spoke. Kakuzu approached him, wearing a bizarre outfit that was completely unsuited for the hot, arid land between the two Lands of Earth and Wind. It was nearly to his knees in length, with long sleeves, and an absurdly high collar. It was completely black, aside from red clouds outlined in white on it.
"Hey, little red runt. Sasori of the Red Sand, isn't it, now?"
"Yes, it is."
"I practically came up with that title. You should be thanking me."
"Thank you." Sasori replied impassively. He wasn't going to lose his temper again.
Kakuzu looked miffed that his bait wasn't taken. Instead, he turned away, and pretended to study a nearby rock. "I've been sent with a…proposition for you."
"You're not here to kill me? I know I have a fairly large bounty on my head." What he hadn't been expecting was this. He was expecting to fight, and to win, and turn Kakuzu into one of his puppets. It wouldn't even come close to his favorite, but it would be an interesting marionette nonetheless.
"I'm not allowed to kill you." That was even odder. Not allowed to? Rogue ninja didn't follow rules. And what was with his outfit? Sasori had a sinking feeling that something wasn't right here. Kakuzu watched flatly as a little white snake slithered over his sandal, twitching a little. "There is a new organization of ninja. The Akatsuki. They're hellishly strong, all of the members so far. The--ah--leader wants you to join."
"Why me?" Sasori asked calmly. But he was beginning to get nervous. He didn't like the prospect of a group of shinobi--wasn't that just like the villages? He didn't deal well with villages. Not to mention the fact that he just plain didn't get along with most other ninja these days. Ever since he defected, he'd became more and more antisocial.
"You're well connected. You're strong." Kakuzu shrugged, and then turned his inverted eyes back to Sasori. "I've seen you do things to a human body I never would have imagined."
"You've been following me."
"Yes. We have."
"Kakuzu, I don't like him." a new voice suddenly announced. Sasori looked around him, thinking that it was some sort of ambush. Instead, Kakuzu sighed and rolled his eyes. "He's too young for this group."
"Excuse me, but I'm fourteen. I hardly think that that's young." the redhead replied to the unknown voice. Then, he caught sight of the little white snake that was coiled on Kakuzu's sandal.
The snake raised its head, and spoke. "You're too young."
"Leader-sama thinks that he'll fit in. He's going to be your partner, Orochimaru."
"And that's precisely why I don't like him." the snake sniffed primly, turning away.
Sasori couldn't believe he was going to start arguing with such a little snake, but here he was. "If my 'partner' is going to be a stupid little snake, I certainly don't want to join this Akatsuki of yours." He smiled thinly. "I don't play well with others."
"Neither do I." the snake hissed, fixing its lidless glare on him. Sasori felt like he should be somewhat annoyed that a snake was talking down to him, but he couldn't quite summon the necessary emotion. "Kakuzu," Now it sounded like the serpent was whining, "let's just go. I don't like him. He's too young and he has no idea how the world works. Entirely too naïve."
"Impressive, if laughable, comments coming from such a tiny snake." The Suna puppeteer kept the fake smile on his face.
And that was how Sasori met Orochimaru and was inducted into the Akatsuki. Granted, he had to be knocked out and literally dragged back to their lair, but he joined the organization regardless. There were only five members (that he knew of): himself, Kakuzu, Orochimaru, a plant-looking man named Zetsu who mostly kept to himself, and the shadowy Leader.
Sasori didn't particularly care about most of them, however. Kakuzu and him got along fairly well, though Kakuzu often would threaten to kill him. Which was nearly impossible, considering some of the modifications he'd made to his own body since he left Sunagakure. But all the same, he'd learned rather quickly that he didn't want to get into a fight with anyone sporting the same uniform as him.
What really caught Sasori's attention was Orochimaru.
His partner was aloof, cool and distant toward him. He was one of the Sannin--some group of highly skilled shinobi from the Leaf. Sasori didn't quite grasp the concept of the title, but he knew that Orochimaru was strong. More than once, in the first year or so, he'd been beaten bloody for an offhand comment or some insult. He had an insane amount of chakra, and could summon snakes in ways that he never would have dreamed of. Orochimaru collected jutsus, and knew far more than anyone else in the organization, though sometimes Kakuzu would hotly deny that.
Moreover, Orochimaru was just beautiful. Almost feminine, but not quite, making him seem more dangerous than he probably was. Long, pure black hair, which contrasted startlingly with his paper-white skin. He would have looked monochromatic if it wasn't for his golden eyes and purple rings around them. He spoke quietly, and quite politely, though he continually called Sasori 'Sasori-chan' until the Suna-nin punched him in the stomach.
For all of his beauty and skills, however, Orochimaru was hopelessly vain. He would constantly mutter to himself things about 'filthy bodies' and related items, which puzzled Sasori, though not unduly. The Sannin would just stare into a mirror sometimes, not even bothering to adjust his hair or clothes like some kunoichi tended to do, but just…stare. Contemplating, thinking, probably wishing for some perfect world where blood would actually look good when it stained clothes.
The missions they were sent on were mundane, bloody, boring things, like single assassinations and spying. Sure, they paid well, but it was a common consensus among the members that their talents were being wasted.
Then, their lives were turned upside down.
Kakuzu got his own partner--a very flirtatious, irritating kunoichi named Yukari--and murdered her in cold blood on their second mission. When questioned about it, he just replied that she had annoyed him. Every partner he had after that met a matching fate. Sasori and Orochimaru were both suddenly glad that they had been put together, instead of with Kakuzu.
But then, they almost met a similar fate. In the form of a Kumo-nin named Yutaka.
By the time he was done with them, they were sent scampering back to the laid with their tails tucked between their legs and nursing various wounds. Sasori had since then converted both arms into puppet limbs; they got injured far too often on missions, after all; he quickly learned to apply the same principles to his legs. He was practically more puppet than human by now, but that didn't particularly bother him.
That was when he learned Orochimaru's secret.
He was immortal.
Sasori learned first-hand how he switched bodies (and was nearly the victim of such an exchange). Sure, there were stipulations, but unless you outright killed him on the battlefield, there was no way that Orochimaru would ever die. He would live forever, just as true art should.
But…that didn't seem fair. Sasori was the artist, not Orochimaru. Orochimaru didn't even know what art was. He scoffed at all of the redhead's ideals and puppets, and just stuck to admiring himself and his jutsus. So why should someone so ignorant about fine art get to reap its benefits?
Sasori decided then that being human was overrated, anyway.
It was a bit tricky to perform the operation to turn the rest of his organic body into wood and wire and chakra, but he managed to pull it off. He hadn't done anything so bloody since creating his marionette of the Kazekage, and he probably would have thrown up at the site of it--if his stomach wasn't lying in a pile with the rest of his useless human organs on the operating table. Still, he gagged, which was actually quite painful, since he didn't have any of the things necessary to make such a thing needed. Sasori practically fell off of the table, careful to ignore his cooling body parts.
He stumbled and fell forward onto the stone floor, his body feeling as if it were lead. Which was silly, since wood was lighter than flesh and blood anyway…Sasori felt his eyes closing.
When he reopened them, he was still face-down on the floor. Blood had slowly dripped off of the table and had made a puddle in the middle of the floor, and he was annoyed to see that a large portion of it had dried on his legs and feet.
Sasori shakily got up, looking around blearily. His mind was told that he was in pain--but that was impossible. Wood didn't feel pain. Only nerve receptors could feel pain, and that was just a body's defense mechanism…it was probably just a phantom pain.
He later found out that it hadn't been phantom pain. His heart--or rather, his chakra--had tried to compensate for the lack of body and filled the wooden joints and limbs with that chakra, giving his mind the sensation of pain, with or without nerves. Of course, Sasori didn't find this out until much later and much experimenting with his new body, though he did figure out that in the same way, he could use his chakra to give him the sensation of touch again.
Sasori leaned heavily on the wall, panting. Again, his mind scolded him; he didn't have a respiratory system, so why the hell would he need more oxygen? The puppeteer chalked that up to psychological trauma, and his body's remaining needs to feel human. In other words, useless, human habit. He'd have to break that.
Sasori wobbly walked over to the full-length mirror. He couldn't believe what he saw.
For all intents and purposes, he was a living puppet. He was more than his Kazekage, Hiruko, or any of his other beloved puppets. He was all wood and metal and wire--and the cylinder that was his heart, still located fondly in his chest. He made a mental note to reinforce its defenses later on. Sasori experimentally moved his arms, watching the way the artificial socket rotated smoothly, and in many more directions than his elbow normally would have allowed him.
Without wanting to, Sasori started smiling. His mouth barely turned upward, but as he continued to examine his new body, it grew wider and wider until it was a full grin. It was more than a grin; it was completely mentally unstable. In some small corner of his mind, Sasori realized that, and ignored it. Who cared? He now had years--no, decades, centuries--to come to terms with the psychological impacts of what this might have done to his mind. He was too busy basking in the glory of being art.
-.-.-
After his operation, Sasori calmed down tremendously. Maybe it was just the lack of hormones, but he didn't feel as angry or temperamental as he used to. Except around Orochimaru.
"You shouldn't be doing that." Sasori lost count of how many times he had to tell his partner that.
"I don't care. Who's going go to stop me? Leader-sama? He's a shadow. Besides, it's all just harmless fun…" Orochimaru would answer every time. And then he'd laugh, that light, airy chuckle that he loved to do. Sasori mostly ignored his deviation, and instead worked on his own missions. And tried to ignore the fact that Orochimaru was right.
The more and more he thought about it, Sasori knew that Orochimaru was right about a lot of things. Leader-sama was nothing more than a shadow. Kakuzu was certainly doing whatever he wanted without reprimand; he had to be on his third or fourth partner by now. Zetsu was hardly seen any more.
So Sasori decided to just let his partner be--while quietly plotting to turn him into his next masterpiece. The Suna-nin couldn't deny it any longer. He hadn't been this obsessed about a person since the Kazekage, and that had ended so nicely… Orochimaru would be a perfect puppet. A huge collection of jutsus at his disposal. And all of those things he could do with his snakes…Sasori often wondered if they would be carried over into a puppet.
But before Sasori could ever have his chance at creating his new favorite puppet, Orochimaru defected from the group. Not officially, but close enough. He went off to live on his own, only coming back for a mission or two when he felt like it. He carried out his experiments in peace, regardless of the Akatsuki's wishes. He hadn't even captured his Bijuu yet!
Not that Sasori blamed him.
Because after what Leader-sama just pulled, he felt like ditching as well.
The leader turned out to be a kid. Or rather, the previous leader had selected this kid to fill his role until he could come up with a better role for himself. There was just no way that this child could be the leader of their organization.
The kid had limp, dark hair that constantly fell into his eyes, and he was always moping around for some reason or another. A nervous-looking, blue-haired girl followed him incessantly, clinging to him as she shrunk from view from the gazes of the other members. Their names were Pein and Konan, and they really were little more than children. Sasori couldn't believe that the leader tried to pass these two off as the next members of the Akatsuki.
Still, as long as they didn't get in his way, Sasori didn't find himself caring much, one way or another. He was too busy stewing in his own anger at Orochimaru's betrayal. Every time he was assigned on a mission with the Sannin, he rejected it and told him to go on it by himself, and hoped fervently that he'd get killed. It never happened, but Sasori was still holding out for it.
In a fit of rage--almost jealousy--Sasori sent one of his best spies into Orochimaru's ranks. He needed to know what his partner was up to, after all. And Kabuto was certainly up for the job. And if not, oh well. He was just a boy; there were plenty of them out there.
Life progressed like that. Sasori would hate Orochimaru, hate him for leaving him there in the Akatsuki, and this kid would pretend to be the leader. Kakuzu killed another of his partners, and a new member, Kisame, soon joined up as well.
Then they got Itachi, and soon after him, Tobi. Pein had progressed--somehow--into a spiky, orange-haired young man, with too many piercings to be comfortable, and ordered them all around with a comfortable ease. Konan, too, matured within the Akatsuki, and soon came into her own with her origami skills. Sasori didn't like how many kids were in the group these days, but it's not like he could really comment. Only Kakuzu and Orochimaru knew about his puppet body, so to all of the others, he probably just seemed like a child as well.
And then, one day, Sasori got the news that Pein's latest pet project actually succeeded in something. Orochimaru was dead. And now this kid would be joining as his replacement.
Sasori held a mock funeral for his dead partner, mostly for the memory of the puppet he never got to have. While they waited for this newbie to catch up with them, he just inserted Kabuto into the little group to keep an eye on him. He didn't want another Orochimaru fiasco.
When Sasori finally met Deidara, for the first time, face-to-face, he suddenly didn't miss Orochimaru at all anymore.