Name : Akasuna no Sasori, "Sasori of the Red Sand", literally "Scorpion of the Red Sand"
Rank : None, Nukenin (Missing-nin)
Position : Left thumb
Partner : Deidara (previously Orochimaru)
Affiliation : Akatsuki, Nukenin (Missing-nin) from Sunagakure (Hidden Sand)
Signature Abilities : Kugutsu no Jutsu (Puppet Technique) (Hiruko, Sandaime Kazekage, himself, etc.), Hitokugutsu (Person Puppets), Aka Higi: Hyakki no S¨en (Red Secret Technique: Performance of a Hundred Puppets), Satetsu (the Sandaime Kazekage's jutsu via the Sandaime Kazekage puppet)
Sasori, Deidara's partner, is a Nukenin (Missing-nin) from Sunagakure (Hidden Sand). In first appearance, he is a hideous hunchbacked figure with a poisoned scorpion-like puppet tail attached. He is known as Akasuna no Sasori ("Sasori of the Red Sand"), the creator of 's puppets and a genius puppeteer in his own right. His first appearance is during their mission to Sunagakure where Deidara is to capture . After Gaara's capture, Kankurou attempts to stop the Akatsuki duo, but to no avail. Sasori battled the enraged brother, nearly killing him and easily destroying Kankurou's puppets in the process. In the end, Sasori was defeated by and Chiyo who controlled Sakura with chakra strings like a puppet as she was familiar with Hiruko and knew its attacks. Later, as the situation gets desperate, as Chiyo's chakra strings are snapped, just as Sasori is about to stab Chiyo with a poisoned katana, Sakura stops him by pulling on the cable in his stomach, despite being poisoned after stabbed in the stomach herself with his katana.
It is revealed that he left the village 20 years before, but the background on his crimes is unknown at this point. Flashbacks seem to indicate that his descent into darkness started when his parents died, and he attempted to simulate being with them by turning their corpses into puppets (the first puppets he ever created). After hearing news of her grandson's return, Chiyo decides to join Team Kakashi in search of the duo and to rescue Gaara.
Sasori and Deidara have quite different views of what art is. Sasori believes art is something that should last, while Deidara believes art is fleeting. Although Deidara respects Sasori's view, Sasori doesn't seem to respect Deidara's.
During combat, and possibly all the time, Sasori "wears" his puppets and controls them from inside, thus eliminating the puppeteer's weakness of being a separate and exposed target. His favorite puppet is named 'Hiruko', according to Chiyo. Hiruko has a mechanical tail extending from the mouth of what appears to be a mask on his back, the left arm is something that appears to be a large studded projectile capable of firing shrapnel, and the clearly artificial mouth opens to reveal a projectile-firing device. What makes him even more frightening, however, was the fact that Sasori makes his puppets out of human bodies, as he stated in the quote. So far, he has a collection of 298 hitokugutsu, (person puppets) made out of human bodies. And to show this, after he was forced to abandon Hiruko, he summoned a hitokugutsu of the Sandaime Kazekage. This puppet was made from the living body of the Kazekage, and thus is able to retain some traits and jutsu of the Kazekage while he was alive.
The truly frightening aspect of Sasori, however, was that his real body is actually as young as he was, and bishonen too. The secret of his youth is revealed after the Kazekage puppet is destroyed: he had made himself into a puppet. His stomach is now hollow, allowing a thick cable to be coiled and stored inside; the cable can act both as a stinger and a support for his body. On his back, a pair of arms, equipped with five large claws, is mounted, and on top of the spine is a scroll holder holding four scrolls, used to summon the puppets for his Aka Higi: Hyakki no Soen (Red Secret Technique: Performance of a Hundred Puppets). Each of his hands now mounts a flamethrower nozzle. His right chest contains a hidden compartment, which can spin unknown numbers of chakra strings to control one hundred or more puppets. Over his heart is a large talisman that has the kanji (Sasori, "Scorpion"). His puppet body can also be pieced back together after being splintered into multiple pieces; this is because the only part of him which is still truly "alive" (and thus able to control chakra) is his heart, located under the talisman. He can also easily transfer the talisman, and by extension himself, between puppets. (How he transfers his face/facial features, as depicted in the manga, is not explained.)
The talisman also proved to be his only weakness, as Chiyo used his mother's and father's puppets to stab him through this location in a manner similar to the hug that he desired. Interestingly, Chiyo seemed to believe that in the end Sasori had allowed himself to be killed - he saw the attack coming and chose not to react, and he died in a way similar to how his parent puppets used to embrace him. At the end of the battle, Chiyo, Sasori, and Sakura are all fatally wounded, but Chiyo uses a jutsu she originally developed for Sasori, "to give life to a lifeless puppet," to save Sakura's life. The jutsu takes the life of the user, but did not kill Chiyo (since Sakura was still alive), until she funneled the last of her life-force through it to revive Gaara after he died.
Sasori's last words were that he has a spy in Orochimaru's ranks, whom he was supposed to meet with in Kusagakure in ten days. This spy is revealed to be Yakushi Kabuto. However, Orochimaru had long ago undone the jutsu on Kabuto that kept him , and Kabuto remained loyal to Orochimaru.