The Twelve Guardian Ninja (守護忍十二士, Shugonin Jūnishi) were a group of twelve elite warriors, who left their village and pledged their lives to protect the Daimyo of the Land of Fire. The members are identified by the "Fire" kanji (火) marked loincloths they wear.
A group formed before the start of the story, the Twelve Guardian Ninja have for a long time protected the Daimyo. All the original members are dead, but the group continues to operate. About ten years before the start of Naruto, half of the original members began to believe that only the Daimyo should lead the Land of Fire and planned a coup d'etat against the Hokage, and later conquer the rest of the countries. Kazuma tried to remove the Daimyo to replace him with a puppet Daimyo, since the Daimyo didn't support the revolting guards, but he was stopped by Asuma. The ideals split the group in two which led to a fight between them, where only Asuma Sarutobi, Kazuma and Chiriku survived. It would seem that some time, before the group was disbanded, some underground organization put a bounty on most of the members.
In the anime filler arc it is revealed that another one of the guardsmen, Kazuma, survived the fight between the two groups. Staying true to his thoughts, he decided that the Land of Fire only needed one king and tried to annihilate Konoha, only to be stopped by and later been killed by Asuma.
During the Hidan and Kakuzu arc, Hidan and Kakuzu went to the Fire Temple to search for the Jinchuriki only to fight Chiriku one of the twelve ninja guardians. Chiriku proved to be formidable but still was defeated and killed by Hidan, Kakuzu later cashed in his body for his bounty of 30 million ryo.
Later at the bounty station Hidan was ambushed by Team Asuma only to surprise the Team by showing them he was immortal. During Hidan's battle with Asuma he ingested some of Asuma's blood and activated his curse that any damage inflicted on him would be inflicted on his opponent. Although the combination of Asuma and Shikamaru was formidable and Asuma even managed to cut off Hidan's head he still survived. After Kakuzu stitched him up Hidan later inflicted more damage to Asuma and finally fatally injured Asuma by stabbing himself in the chest, killing Asuma.
- Kazuma (Killed by Asuma after attempting to destroy Konoha, deceased)
- Kitane (Killed by Kazuma. Later resurrected and then killed by Asuma, deceased)
- Nauma (Killed by Kazuma. Later resurrected, but summon released by Kazuma, deceased)
- Tōu (Killed by Kazuma. Later resurrected, but summon released by Kazuma, deceased)
- Seito (Killed by Kazuma. Later resurrected, but summon released by Kazuma, deceased)
- Asuma Sarutobi (Killed by Hidan, deceased)
- Chiriku (Killed by Hidan and Kakuzu, deceased)
- Shikamaru Nara. Received an invitation from the Daimyo of the Land of Fire to become one of his guards, which would have led to becoming a member of the elite Twelve Guardian Ninja. But refused saying he'd rather stay in Konoha and protect his friends.