The Akatsuki remained one of Naruto’s most feared antagonist factions, posing a threat to the entire shinobi world till the very end of the series. The group possessed many fearsome fighters, with some even obtaining the secrets to immortality. However, out of the four members that had gained permanence, Kakuzu was the only one that was organically immortal. The secret to his eternal life lies in the forceful extraction of his enemies' organs, and while it may sound quite simple, the process certainly isn't.
Kakuzu was the oldest member of the Akatsuki, dating back to the times of the First Hokage. Since then, he had prolonged his life through the hearts of his defeated opponents, and while his eternal life still had several limitations, he could increase his lifespan as long as he had the bodies of his victims. However, Kakuzu's immortality had several intricacies to it, adding up to his organic yet gruesome permanence.
The Origins of Kakuzu's Immortality
Kakuzu's immortality, along with his villainous origins, can be traced back to his time in the Hidden Waterfall Village. Once an elite ninja of his home village, Kakuzu was deemed a failure when he failed to assassinate the First Hokage, Hashirama Senju, prompting ridicule and disappointment from his own people. Despite his loyalty to the village, the elders punished Kakuzu for failing the mission by imprisoning him, giving way to disdain and contempt to creep into his heart.
Angered by the brutal punishment and harsh treatment, Kakuzu betrayed his nation and fled the Hidden Waterfall Village, though not without slaughtering the village elders and stealing their forbidden techniques. One of these jutsu was the Earth Grudge Fear technique, a prized jutsu of the Hidden Waterfall, capable of granting the wielder near-permanence. Through the Earth Grudge Fear technique, Kakuzu could transform his body into hundreds of thick threads, with his limbs almost sewed together with these needle-like appendages.
After betraying his village and becoming a rogue ninja, Kakuzu became a bounty hunter, working within the black market to make a living by cashing in the rewards on his victim’s heads. Considering Kakuzu was alive during the times of Hashirama Senju, he could very well be the oldest living person in the series, though he’s most certainly the oldest out of all four of the Akatsuki’s immortal members.
Earth Grudge Fear Technique
The Earth Grudge Fear technique is the secret behind Kakuzu’s immortality, allowing him to prolong his life through the vitality of his victims. The jutsu was once a secret technique belonging to the Hidden Waterfall Village, though it was later stolen by Kakuzu once he defected from the village. The technique turns the wielder’s body into a ragdoll of sorts, with thick threads protruding out of the body. These threads are capable of detaching limbs from the body, which can then be sewed back by the thick tendrils.
The interwoven threads serve many purposes, with Kakuzu’s primary usage being the extraction of vital organs from his enemies’ bodies. He could penetrate into his opponent’s body, carefully extracting the organs with his threads and slowly assimilating them back into his own body. However, his primary target would be the hearts of his victims, as this vital organ is the true essence of Kakuzu’s eternal life.
Kakuzu could implant up to five beating hearts into his body at the same time, and for him to be slain, all five of his hearts had to be destroyed. Once a heart is damaged, Kakuzu can quickly replace it with another one by stealing it off one of his victims. These extra hearts are attached to Kakuzu’s body in the form of animal masks, which can even detach from his body to become independent entities, with each mask being adept in a different type of elemental release.
The Secret to Ending Kakuzu’s Permanence
While Kakuzu was mostly immortal due to his secret technique, he never considered himself to be an immortal being – and rightfully so, as he could still be killed if he faced an opponent strong enough to take on his masked hearts. Until every single one of his hearts had been slain, Kakuzu could still fight at full strength, meaning ending his life once and for all requires every single mask to be destroyed, along with the last heart in his chest.
Kakuzu was eventually slain by Kakashi and Team 10 using this very method, as the invulnerable shinobi that once seemed immortal possessed several weaknesses. Once the team figured out the intricacies of the Earth Grudge Fear technique, defeating Kakuzu simply became a matter of using brute force to slay every last heart. In a way, Kakuzu was right to believe that he was never immortal, as his life may have been prolonged by several decades, yet it did eventually conclude, just like any other mortal.