Kakuzu was a tan-skinned and tall man, easily standing as the second tallest member of Akatsuki. Noticeably, despite his advanced age, he still appears as a man well within his prime, retaining a very muscular build. He wore a white hood and a black mask, with his eyes being the only visible part of his face. Underneath, his mouth was stitched together at the edges (giving him a glasgow smile) and he had long dark brown hair. His eyes have an unusual coloring: green irises, no pupils and red sclera. His clothing included the traditional Akatsuki cloak and the forehead protector of his home village with a scratch in the middle which symbolized that he was no longer loyal to it. He also wore brown nail polish and his dark green Akatsuki ring with the kanji for "north" was placed on his left middle finger. His entire body was covered with various stitches and predominantly appeared to be sewn together. This was a result of the unique technique that he possessed - the Earth Grudge.
Kakuzu was a greedy and miserly individual, arranging goals in terms of the highest profit he could gain from them, and was often unwilling to involve himself in something if there was nothing to gain from it, as well as claiming that he tended to forget opponents who were not worth any money after he was done with them. He even remarked that money is the only dependable thing in the world. Due to this end, he referred to himself as the "Treasurer of Akatsuki". Given his friendly relationship with Zangei, his bounty officer, it would seem he collected bounties rather frequently to 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 well, 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 of them were very fond of each other's interests. The two often traded barbs with one another, Kakuzu's usually having better timing than Hidan's. Hidan had 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. Despite their mutual dislike of each other, their teamwork was almost flawless, because they complemented each other's abilities extremely well. Also, Kakuzu seems to care to an extent about Hidan, as he picked up and gave back his partner's forehead protector after he lost it during his fight with Asuma, a feat that made Hidan admit that Kakuzu is not as hostile as he appeared to be.
The only reason that Kakuzu put up with Hidan was because he couldn't get rid of him. Due to his violent temper, Kakuzu often killed anyone close by when enraged. Hidan, therefore, was the perfect partner for Kakuzu, because of Hidan's inability to die. Kakuzu's somewhat indiscriminate attack style also made Hidan an ideal partner, since Kakuzu didn't need to worry about catching his partner in the crossfire.
Despite his obsessive personality and violent rages, 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 also 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. 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 jinchuriki alive.
Kakuzu held a violent hatred for his village, as despite his loyalty and willingness to risk life and limb on a dangerous mission, his failure was repaid with uncharacteristically harsh punishment. He responded in kind by brutally betraying the Hidden Waterfall committing jailbreak, taking knowledge of their most valuable kinjutsu and killing all of the elders before departing.
Despite his greed and his temper, Kakuzu was shown to be very dutiful to the Akatsuki. When Nagato, known as Pain at the time, told them to return to a hideout to seal the Two-Tails, Kakuzu immediately returned without asking for more time to retrieve Asuma's body and cash it in for money.
Earth Grudge: All of Kakuzu's abilities revolved around his unique body structure, which was composed of hundreds of thick, grey tendrils woven throughout his flesh called Earth Grudge, holding his body together like the stitches of a rag-doll. This allowed him to separate his body parts at will, perform long-range physical attacks, and sew up almost any injury he suffered. All these abilities made him very difficult to defeat. The threads could also be used to repair the bodies of others, as seen when he reattached Deidara's arms, although Hidan's inability to die after being dismembered caused him to be Kakuzu's most frequent patient. Because of his unique body structure, Kakuzu is a highly enduring man, able to take a direct strike from Kakashi's Lightning Blade without it hindering his performance. His threads could even compact together to form a giant octopus-like form around his body, used for long range battle. Kakuzu's threads granted him a degree of immortality (though he declined 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 commonly removed hearts in this fashion, keeping a total of five at any time, and requiring that he be killed at least five times in a battle before he truly died. If Kakuzu was killed somehow, then one of his extra hearts could sacrifice itself by re-entering his body and bringing him back to life.
Nature Transformation: The hearts captured from other ninja granted Kakuzu numerous elemental affinities, along with a vast supply of chakra. By collecting these hearts, Kakuzu's own affinity is reinforced and his skill in other elements is increased to the point that he could use various different elemental attacks that were noted to be impossible, without having an affinity to that particular element. This is done by connecting his chakra circulatory system to his four extra hearts, granting him the ability to change his chakra nature and affinity to that of the previous owner. 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. The hearts that Kakuzu had stolen prior to his death, belonged to his previous partners in Akatsuki. In the Naruto anime, Kakuzu could use water-based techniques like the Water Formation Wall technique when Shikamaru threw an explosive tag at him. He was also capable of creating a water clone and hiding within water as seen during his fight with Kakashi.
- Earth mask: This heart had an earth affinity, and took on the shape of a demonic, beaked biped. It allowed Kakuzu to use Earth Style: Earth Spear. In the Naruto anime, even though this mask was destroyed, Kakuzu was still able to use the Earth Spear technique, though it only hardened his arm.
- Fire mask: This heart had a fire affinity, and took on the shape of a demonic tiger. It could use Fire Style: Searing Migraine. This mask could also unite with the Wind mask to launch a fire-wind dual strike that was near unstoppable.
- Lightning mask: This heart had a lightning affinity, and took on the shape of some sort of deformed biped. It could use Lightning Style: False Darkness.
- Wind mask: This heart had a wind affinity, and took on a strange four-legged body with thin wings. It could use Wind Style: Pressure Damage. It could unite with the Fire mask to launch a fire-wind dual strike that was near unstoppable.
- Immense Strength: His raw strength was great enough to catch one of Choji's enlarged punches with a single hand, as well as send an opponent flying with a single kick. He could also lift both Choji and Ino by their necks with relative ease.
- Immense Speed: Kakuzu has demonstrated great raw speed, able to cross great distances in the blink of an eye and disappear from unfocused eyes. He was fast enough to intercept Kakashi when he was attacking Hidan with his Lightning Blade.
- Enhanced Reflexes:
- Immense Durability:
- Immense Endurance:
Keen Intellect: Kakuzu was shown to be a keen analyst, which was somewhat attributable to his advanced age. He is highly 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. 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. An example is when Shikamaru trapped him and Hidan in his Shadow Possession Shuriken Jutsu, only for Kakuzu to detach his right arm, hide it underground and with its help, remove the trench knife, thus successfully breaking free from the technique.