Name : Kakuzu (Deceased)
Age : ?
Height : ?
Weight : ?
Ring : Hoku, north
Ring position : Left middle finger
Partner : Hidan
Debut : Chapter 312; Episode 135 (unnamed silhouette)
Unique traits : High physical strength, extremely obsessed with money
Kakuzu is a missing-nin from Takigakure and 's partner. Hidan and Kakuzu display the most animosity towards each other out of all members of Akatsuki, with neither being very fond of the other's interests. The two often trade barbs with one-another, Kakuzu's usually being better timed than Hidan's. Hidan gets annoyed with Kakuzu's greed and occasional habit of doing or saying blasphemous things, such as attacking a temple and killing the head monk for the bounty on his head. Kakuzu, in turn, doesn't like Hidan's religion at all, believing the rituals associated with it to be a waste of time, and is also impatient with Hidan's drawn-out speeches and battle style. The reason Kakuzu deals with Hidan is because he's quick to anger, and will often kill anyone in sight when enraged. Hidan is the perfect partner for Kakuzu because of his apparent inability to die. Kakuzu's somewhat indiscriminate attack style also makes Hidan a perfect partner, since Kakuzu need not worry about catching his partner in the crossfire. The first kanji in Kakuzu's name stands for kakugyou, a bishop in shogi.
Kakuzu is a greedy individual, often arranging goals in terms of the highest profit he can gain from them, something his partner cannot stand. He even comments on money being the only dependable thing in the world and that he wouldn't mind hell because money runs it. Due to this view of money, he refers to himself as the Treasurer of Akatsuki. Given his friendly relationship with a bounty officer, it would seem he collects bounties rather frequently to earn cash, and does so (or at least tries) during his missions on several occasions, which is another point of infuriation for Hidan. He even looks at Hidan's religion through his ability to earn money from it, which is why he puts up with it.
Despite his obsessive personality and violent rage, Kakuzu is much more cautious than his partner, frequently warning Hidan to not let his guard down then teasing him when he inevitably does. Kakuzu is shown to be a keen analyst, as well. He was able to quickly discern the purpose of Shikamaru's various shadow attacks and devise ways to counter them almost instantly during battle. He also seems to be more willing to take orders. When ordered to retreat by the Akatsuki leader, Kakuzu complied immediately while Hidan attempted to argue, despite the rather large bounty he could have gotten on Asuma Sarutobi at the time. However, he does make it a point to retrieve the case with his bounty.
Kakuzu reveals the masks sewn onto his back.Kakuzu's entire body is strung together with a thick, black thread that Kakuzu can control at will, giving him an appearance reminiscent of Frankenstein's monster. By undoing the threads holding the pieces of his body together, Kakuzu can extend his limbs or repair any damage inflicted upon him. Kakuzu can also use his threads to reattach the severed limbs of others. In addition, Kakuzu can also utilize the threads offensively. He can extend a great number of threads from his body and stretch them to formidable lengths to ensnare and immobilize opponents, then use the threads to pierce their bodies or tear their hearts from their chests.
Kakuzu also uses his threads to prolong his life indefinitely. By taking the hearts of his opponents while they're still alive and incorporating them into his own body, Kakuzu is able to use their hearts as his own. He keeps a supply of five hearts at any given time, making the chance of his hearts all failing unlikely at best. When one of his hearts is worn away naturally or is destroyed, he can simply replace it. Combined with his sewn-together body, the five hearts make Kakuzu effectively immortal, since all five must be destroyed to kill him. Having five hearts also allows Kakuzu to control his various body parts remotely by attaching a heart to any separated body part. Kakuzu has apparently lived for quite a long time through this method, since he mentions that the first Konoha ninja he fought was the .
Kakuzu's four extra hearts are normally attached to four masks sewn onto his back, each one resembling a demonic animal. The visible three resemble an eagle, a lion, and an ox. The fourth is damaged by 's Lightning Blade before being unveiled, so it's unclear what animal it is intended to resemble. Because the masks each hold a separate heart, each can utilize chakra separately. When Kakuzu unsews the masks, they burst from his back and form bodies vaguely resembling their animal with the same thread that holds Kakuzu together. Each mask creature is able to control and attack with a specific chakra element: the eagle uses wind, the lion uses fire, and the ox uses lightning. These bodies can merge together to allow combination elemental attacks to be used. When all four are intact, Kakuzu has the potential to control all five chakra elements simultaneously. The masks are maintained by the hearts within them and shatter should the heart be destroyed or removed. Kakuzu can do this willingly in cases where his active heart is destroyed.
Finally, Kakuzu has an earth-based jutsu that hardens his body, increasing his strength and rendering him virtually invulnerable to any physical attack. So far, only Kakashi Hatake's Lightning Blade has been able to beat this technique, which is due to the natural weakness that earth-based jutsu have to lightning-based jutsu. It's not clear if the broken mask is responsible for this technique or if Kakuzu has a natural affinity towards earth.
Kakuzu has a unique body structure that consists largely of thick black threads running throughout his body, which he can use to detach parts of his body for long range assaults. The threads themselves can also be used for attack, being able to pierce the bodies of others with relative ease. These threads are apparently limitless, as Kakuzu can use them to change his appearance and visually increase his size several times over as a result. Kakuzu's threads also allow him to integrate foreign organs into his system, allowing him to extend his life indefinitely by taking the healthier organs of others. He has used this ability to lengthen his lifespan by a great deal, as he claims to have fought the First Hokage at some point in his life. Kakuzu most prominently uses hearts in this way, keeping up to four extra hearts with him at any given time. He keeps his spare hearts stored within animal masks sewn to his back, and each of the masks can separate from his body and attack independently.
Once removed from his body, the masks can utilize powerful blasts of elemental chakra, with each blast being given its own name: Fire Release: Intense Pain , Wind Release: Pressure Damage and Lightning Release: False Darkness. These masks can also combine to increase the potency of their attacks, with one element gaining strength as a result of a second. If the heart in Kakuzu's body is destroyed, one of the masks can quickly remerge with him so that he can take use of its heart, causing the mask to crumble away. In the event that he loses one of his hearts, Kakuzu seems to prefer taking the heart of the opponent responsible, prolonging his life from the strength of his enemy. Kakuzu also has an earth-based defensive jutsu referred to as Iron Body, which increases his strength and makes him virtually immune to physical attacks. It is not clear if this ability is a result of his fifth heart, or if it is that of his fourth mask.
As Kakuzu and Hidan make their way to Konohagakure to finish an earlier battle, the two are met by a group of four Konoha ninja. Soon after the battle starts, Kakashi Hatake is able to pierce Kakuzu with his Lightning Blade, destroying one of his masks. His current heart being unscathed, Kakuzu brings out his other three masks with which to attack the Konoha ninja. While he is able to gain the upperhand, Shikamaru Nara is able to trick Hidan into using his voodoo-like ability on Kakuzu, causing him to lose one of his hearts. After taking the heart from one of his masks Kakuzu prepares to finish off the group, though the arrival of reinforcements stops his attack. Naruto Uzumaki, the host of the Nine-Tailed Demon Fox, does battle with Kakuzu and is in time able to strike him with his Wind Release: Spiraling Shuriken, striking Kakuzu at a cellular level and severing all of his nerves. Losing his two spare hearts and leaving his other heart on the verge of failure as a result of the attack, Kakuzu is left defeated and unable to move. With the last of his strength he attempts to figure out how he could be defeated by some "kids", which Kakashi attributes to the natural progression of things before finishing him off.