Kakuzu was an S-rank rogue-ninja from the Hidden Waterfall Village and a member of the Akatsuki who was partnered with Hidan. Kisame Hoshigaki jokingly referred to them as the "Zombie Brothers", due to the fact that, in a sense, they could not die. Within the organisation itself, Kakuzu acted as the organisation's treasurer.
When he was still a loyal, elite ninja of the Hidden Waterfall Village, Kakuzu took on a mission to assassinate Hashirama Senju, the First Hokage. This mission, however, ended in failure due to the might of Hashirama's Wood Style techniques. Despite the insurmountable danger faced in the mission, what awaited his return to his village was the stigma and harsh punishment associated with the failure of his objective. In response to this treatment, Kakuzu came to hold a violent hatred for his village 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. He made a living off bounty hunting in the black market, and tearing out the still-beating hearts of powerful shinobi to extend his own lifespan. Some time after his defection, he joined Akatsuki, and was given a number of partners, most of whom he killed, due to his short temper. This is why he was eventually partnered with Hidan, whom he could not kill because of his immortality.
All of Kakuzu's abilities revolved around his unique body structure, which was composed of hundreds of thick, dark grey threads 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, to 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. The threads also granted him a degree of immortality. 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.Full biography at NarutopediaWith CloakAkatsuki Partner