Kakuzu

was the partner of Hidan despite their mutual dislike of each other. Kisame laughingly referred to Hidan and Kakuzu as the "Zombie Brothers". The first kanji in Kakuzu's name (角) stands for kakugyō, the bishop in shogi.

Background
As an elite ninja from Takigakure (the Village Hidden among Waterfalls), Kakuzu took on a mission to assassinate the First Hokage. This mission, however, ended in failure before the might of the First Hokage's Mokuton jutsu. Despite the insurmountable danger faced in the mission, what awaited his return to his village was the stigma and harsh punishment associated with failure of his objective. In response to this treatment, a wrong levied against a shinobi who had put life and limb on the line for his village, Kakuzu came to hold a violent hatred as he escaped from imprisonment. In his flight from the village, Kakuzu killed the village elders, took their hearts, and fled with knowledge of the village's most prized forbidden techniques. In addition, in about 30 years later, he would join Madara Uchiha and form the Akatsuki.

Personality
Kakuzu was a greedy, miserly individual, arranging goals in terms of the highest profit he could gain from them, and was often unwilling to involve himself in something unless there was something to gain. He even remarked that money is the only dependable thing in the world; therefore, he wouldn't mind going to hell because as he said, "They say money makes the underworld turn as well. Can't say I'd complain." Due to this point of view, he refered to himself as the Treasurer of the Akatsuki. Given his friendly relationship with Genji, his bounty officer, it would seem he collected bounties rather frequently earn cash, and did so (or at least tried) during his missions on several occasions. The frequent side tasks and devotion to money were both major points of contention between Hidan and Kakuzu. He also seemed to respect an opponent who thinks, as shown with his reaction to Kakashi's counters to Kakuzu's masks and Shikamaru's quick analysis of Hidan's curse, even mentioning Shikamaru would have been a good bounty in the future.

Out of all the Akatsuki members, Hidan and Kakuzu displayed the most animosity towards each other, since neither were very fond of the other's interests. The two often traded barbs with one another, Kakuzu's usually having better timing than Hidan's. Hidan has shown great annoyance 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 the monk's head. Kakuzu, in turn, disliked Hidan's religion, believing the rituals associated with it to be a waste of time. Kakuzu was also rather impatient with Hidan's drawn-out speeches and battle style.

The only reason Kakuzu put up with Hidan was because he can't get rid of him. Due to his violent temper, Kakuzu often killed anyone close by when enraged. Hidan was, therefore, the perfect partner for Kakuzu, because of Hidan's apparent inability to die. Kakuzu's somewhat indiscriminate attack style also maked Hidan an ideal partner, since Kakuzu need not worry about catching his partner in the crossfire.

Despite his obsessive personality and violent rage, Kakuzu was much more cautious than his partner and was not as arrogant, never mindlessly rushing into battle like Hidan. Kakuzu frequently warned Hidan not to let his guard down, and then teased Hidan when he inevitably did. Kakuzu was shown to be a keen analyst as well, which was somewhat attributable to his age. In the anime, he seemed somewhat more observant, easily noticing that Shikamaru was taking his time to formulate a plan to counter Hidan's technique after the former caught his partner in his Shadow Possession Jutsu. (His age gave him several lifetimes of battle experience.) He was able to quickly discern the purpose of Shikamaru's various shadow attacks and devised ways to counter them almost instantaneously during the battle. Despite his status as a missing-nin, Kakuzu apparently seemed quite willing to follow 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 received by taking Asuma. However, Kakuzu did make it a point to retrieve the case with his bounty although he seemed to forget the greater goals of the organization when enraged, as he attempted to kill Naruto in spite of Akatsuki's need to capture all the Tailed-Beasts alive.

Hidan and Kakuzu arc
Kakuzu first appeared with his partner, Hidan, in their pursuit of the Two-Tailed Demon Cat's host, Yugito Nii. She allowed herself to be cornered in order to spring a trap on them and eliminate them herself. Yugito then transformed into her full demon form, a large flaming cat, after Hidan provoked her (which annoyed Kakuzu); Kakuzu claimed Hidan just made their job more difficult. Despite her efforts, the two defeated her and Zetsu arrived to drag her off. Kakuzu then noted that their next target would be in the Land of Fire. In spite of the implication, they were apparently not chasing Naruto, as indicated by a later conversation with Deidara.

On their way, Kakuzu decided to attack the Fire Temple in order to collect the bounty on the head monk, Chiriku, who was a former bodyguard for the Fire Country's nobility.; Chiriku was listed in the bingo book with a thirty million ryō bounty. They slaughtered most of the other monks during the event, but one escaped to warn Konoha of the incoming threat. While the Niju Shotai are mobilized to deal with the pair, Kakuzu was stuck carrying the head monk's corpse.

One Niju Shotai team consisting of Asuma Sarutobi, Shikamaru Nara, Kotetsu Hagane, and Izumo Kamizuki caught up to the duo at a bounty station, where Kakuzu was cashing in the deceased monk. For the most part, Kakuzu let Hidan fight, only intervening when Hidan finally asked for help when the latter was decapitated. Being immortal, Hidan survived, and Kakuzu repaired the wounds using the threads in his body. Kakuzu then fought with Kotetsu and Izumo, easily holding the two off while Hidan dealt a fatal blow to Asuma. Their battle is interrupted by the appearance of another Niju Shotai team, this one consisting of Ino Yamanaka, Choji Akimichi, Raido Namiashi, and Aoba Yamashiro. Kakuzu was unwilling to leave Asuma behind, since Asuma had a substantially higher bounty than the monk he just cashed in by 5 million ryō, but was forced to retreat by Pain, who wanted to seal the tailed-beast of the recently captured jinchūriki.

After the sealing was complete, Kakuzu and Hidan set out on their search again, only to be cut off by Team 10 (with Kakashi Hatake in place of Asuma). Kakuzu habitually noted that Kakashi has a high bounty. A clever move by Shikamaru pined both Akatsuki members in place, but Kakuzu discovered the trick beforehand and, using a separated arm, broke free. Because of his ability to harden his skin, Kakuzu proved to be largely invulnerable to subsequent attacks. Kakashi, however, was able to pierce Kakuzu's heart with his Lightning Blade, exploiting the weakness Kakuzu's earth-based jutsu have against lightning-based ones.

While this would normally be fatal, Kakuzu had five hearts (now four) in his possession, and thus recovered fairly quickly, sending a counterattack to Kakashi. Removing his cloak, he revealed four masks on his back, one of which was now broken by Kakashi. Each mask contained a heart, the broken one having given its heart up to keep Kakuzu alive. The four masks broke free from his back into separate entities, with the broken one dissolving after doing so. Each mask was able to attack with a specific and powerful elemental attack, making Kakuzu almost too much for Team 10 to handle. While Kakuzu set his sights on replacing his lost heart with Kakashi's, Shikamaru dragged Hidan away from the battlefield for a one-on-one fight.

Ignoring the other two for the most part, Kakuzu focused on taking Kakashi's heart. He did note that Shikamaru could have been collected as an impressive bounty had he lived longer (as he believed the latter was doomed). Though Kakashi was unable to handle Kakuzu and his mask creatures, he was saved when Shikamaru tricked Hidan into using some of Kakuzu's blood in his curse ritual (Kakashi had collected it earlier when he pierced Kakuzu's chest); This resulted in Hidan unintentionally destroying Kakuzu's Lightning Mask. Though slowed, Kakuzu adapted quickly by combining the entities of the Fire and Wind Masks. He then caught the rest of Team 10 with his threads, hoping to replenish his stock.

Team 10 was saved by the arrival of Team 7, consisting of Naruto Uzumaki, Sakura Haruno, Yamato, and Sai. Naruto decided to fight Kakuzu himself, while Sakura and Sai were sent to help Shikamaru. Kakuzu was able to identify Naruto immediately, thanks to the missing-nin's earlier conversation with Deidara, although at first was not concerned. This changed when Naruto unveiled his Wind Release: Rasenshuriken, which Kakuzu recognized to be dangerous if it ever connected. Naruto's inability to maintain the technique for more than a few seconds put him at ease, especially since its failure almost allowed him to kill Naruto (although Yamato and Kakashi saved him), but decided to fight long range just to be safe. Using his threads, Kakuzu attempted to crush Naruto from a distance, but was surprised when the real Naruto shoots up behind him, using the technique effectively this time.

Left with no usable hearts after being battered by Naruto's technique, Kakuzu lamented being defeated by those he considered "kids". Kakashi assureed Kakuzu that the previous generation being surpassed by the next was perfectly natural and one of the "never-ending cycles of life"; Kakashi then finished him off with a Lightning Blade.

Unique Body Structure
All of Kakuzu's abilities revolved around his unique body structure, which was composed of hundreds of thick dark gray threads woven throughout his flesh called Earth Grudge Fear, holding his body together like stitches of a rag-doll. This allowed him to separate his body parts at will to perform long-range physical attacks and sew up almost any injury he suffers, making him very difficult to defeat (Although it was proven that Kakuzu had internal organs and blood, he somehow didn't injure himself when separating his body parts in this fashion).

The threads could also be used to repair the bodies of others, as seen which he reattached Deidara's arm, although Hidan's inability to die after being dismembered causes him to be Kakuzu's most frequent patient. Kakuzu could use his own body's threads to attack from long-range and restrain or dismember opponents. His threads could even compact together to form a giant spider-like form around his body. It should be noted that these threads were very durable.

Physical Prowess
Kakuzu was also shown to be a very skilled dangerous close range fighter. He demonstrated surprising speed for his size that unfocused eyes have difficulty keeping up with as he was able to cross gap between him and his opponent instantly. His raw strength was great enough to catch one of Choji's enlarged punches with a single hand and punch down an iron gate, as well as lifting and choking two people simultaneously. His taijutsu skill has shown to be very high as well during his fight with Kakashi (who was quite skilled in taijutsu himself) as he easily gave him a very hard time, by mixing his hardening and stretching abilites with his taijutsu.

Longevity and Experience
Kakuzu's threads granted Kakuzu a degree of immortality (though he declines to think of it that way). The threads could pierce the flesh and bodies of others, allowing him to remove their organs and integrate them into his own body, thereby extending his life. He most commonly removed hearts in this fashion, keeping a total of five at any time; Four of them are stored in animal-shaped masks on his back. With five hearts, Kakuzu essentially must be killed a total of five times before he could truly die.

Kakuzu could also draw on his lifetimes of experience to keep ahead of his opponents and outmaneuver their attacks. After having lived over 90 years, Kakuzu felt there was nothing he hasn't seen in combat and believed there was no tactic he wasn't prepared for.

Five Elements
The hearts captured from ninja granted Kakuzu numerous elemental affinities and a vast supply of chakra. The raw power of each element Kakuzu demonstrated even made Kakashi, who is also capable of multiple elements, stiff with awe. The individual hearts could be released from his body and wrapped in a vast blanket of threads, forcing a heart into a limb before being detached or forming a monstrous body with a mask as its face. These masks could move and attack independently, unleashing powerful blasts of elemental chakra from their mouths.


 * Fire - A bear -like mask with red lips, it formed a hunched backed-shaped body and could fire huge waves of flame, which spreaded across the ground consuming everything it touched within a half mile radius. These explosion of fire spreaded out in every direction. It can fuse with the eagle mask to create a dual fire/wind attack that was almost impossible to stop.
 * Lightning - A bull-like mask with a deformed bipedal body along with a yellow nose, it could unleash deadly twin lightning bolts.
 * Wind - An eagle-like mask with a strange four-legged body and thin thread wings and blue markings on it`s mouth, it could project huge hurricane-force air blasts that were capable of leveling a large region of forest. It can fuse with the bear mask to create a dual fire/wind attack that was almost impossible to stop.
 * Earth - This last mask was broken by Kakashi Hatake before being seen, though a brief glimpse of its side suggested that it might have been a pig mask. Kakashi confirmed its earth-based nature after watching the corresponding hand seals and Earth Spear technique, and defeated it with a technique utilizing lightning chakra, the weakness of earth.
 * Water - Although it was never revealed on the manga, Kakuzu could use the jutsu in the anime assuming his water heart is his original.

Overall Strength
Kakuzu's overall level in strength made him one of Akatsuki's physically strongest members, as every opponent he had been seen defeating had been defeated with only an ounce of his potential. This is shown in Kakuzu's fight with Chiriku, Yugito, and Asuma (all of whom being on Jonin level of strength or higher). In addition, during the fight against Team 10, Kakashi, and Naruto, it took two Lightning Blades, Hidan's ritual, a Rasen Shuriken, and Shikamaru's genius and tactics, just to kill him.

Quotes

 * (To Hidan) "I will kill you. "
 * (To Hidan) "Better the arms than the head."
 * "Don't let your guard down or you'll die."
 * "Make sure he's recognizable when you're finished with him."
 * "They say money makes the underworld turn as well. Can't say I'd complain."
 * "Looking at your forehead protector reminds me of the very first Konoha shinobi I fought..., the First Hokage, that is."
 * "Shut up, Hidan."
 * (To Shikamaru) "You actually think, unlike my partner."
 * "Says the guy whose head got chopped off."
 * (To Hidan) "Keep talking and I will kill you."

Trivia

 * Both Hidan and Kakuzu made their first video game debuts in Naruto Shippūden: Gekitou Ninja Taisen EX 3.
 * Although covered by his hood, Kakuzu has long hair, almost at shoulder length.
 * There are many likelinesses between Zabuza and Kakuzu. They were both born on August 15, both dead, both mask their faces, both tried and/or went up against a kage, and both came close to dying in fights with Kakashi by the Lightning Blade.
 * According to Pain, Kakuzu's reason for fighting is "Resources".
 * When Kakuzu first appears as a hologram at the end of Part I, he is clearly the tallest Akatsuki member there, a fact reinforced when he appears during Gaara's sealing ritual. However, when he truly appears with Hidan he is much shorter, and the 3rd databook states that he is shorter than Kisame.
 * It's possible that because of having multiple hearts, it would give Kakuzu increased blood flow throughout his entire body which could explain why his eyes are all red. The elevated blood flow could also be the reason for his immense strength.