Hidan was a former member of Akatsuki, paired alongside Kakuzu. He had a immortal body due to which physical attacks didn’t affect him and he stayed alive even after his own head got decapacitated. There isn’t a whole lot of information about Hidan’s immortality and is never explained in the canon story. But there is few info from other sources such as fanbook and Boruto Anime which gives us insights about his immortality.
How is Hidan immortal? Immortality Jutsu
As one might have guessed, his immortality is tied to the religion Jashin. The way of Jashin uses bodies of believers in a forbidden jutsu ritual. As a reward for many of his massacres, Hidan acquired an immortal body. He is the first successful case to acquire so we can assume that nobody else has immortal body. His complete belief in The Way of Jashin is due to him acquiring immortality.
Though Hidan specifies his immortality as a power due to his way of Jashin, it is actually just one of forbidden Jutsu requiring several sacrifices. In a way it is similar to Summoning: Impure World Reincarnation technique that summons dead people back to the real world by using a living body.
Addition info about Immortality in Boruto
In Boruto – Next Generations, Kakashi, Guy and Mira (daughter of Asuma) goes to the Land of Hot water for a mission. Ryuki, a member of Land of Hot Water and also a follower of Jashin and Hidan tries to attain immortality by sacrificing several young girls. From this it is pretty clear that several living people have to be sacrificed for attaining immortality.
Cursed Art: Blood Rite Death
Hidan acquired this curse technique through his Way of Jashin. After ingesting blood of the target, target is inflicted with same wounds as the caster inflicts upon himself. Thus Hidan alone can use this technique since it involves the caster to injure himself and only Hidan with his immortal body can perform it. The caster will have Grim Reaper like patterns all over his body.
Steps to perform Curse Art ritual:
- Caster has to drink target’s blood.
- The caster must enter into a symbol drawn by caster’s own blood.
- The injury suffered by caster will be equally suffered by the target.
Relation between his Immortality and Cursed Art Technique
His immortality technique and his cursed blood rite death are independent of each other. But the immortality allows Hidan to use the Cursed Art technique since only he can remain alive using it. Others can use Cursed Art technique but will end up killing itself since one has to injure herself to perform this technique.
In Boruto Anime, Ryuki uses a slight variation of this, Curse Technique: Body Controlling Manipulated Blood. By using this he controls another person via a puppet by injecting their blood initially. The controlled person has the same Grim Reaper like pattern on her body as Hidan has when he performs the Curse. This can be a confirmation that both Immortality and Cursed Art technique are independent of each other.
Immortality Jutsu Weakness
Only way to kill Hidan is to malnutrition him. He stayed alive even when his head was decapacited by Asuma.
Cursed Art Technique weakness
Hidan will also feel the pain when he is inflicting injuries to himself. He has to stand in the symbol to perform this technique and it takes time to start the ritual.
Kakuzu and Hidan – Immortal Combo
The only reason Hidan joined the Akatsuki is his interest about Kakuzu‘s immortal body like himself. Hidan considered Kakuzu as his predecessor. Since Kakuzu cannot kill Hidan, there will no need to change partners when Kakuzu enters his fits of rage which previously has killed his partners. Kakuzu and Hidan though disliked eachother used immortality to their advantage since they can both attack freely.