Kamen Rider Zanki (仮面ライダー斬鬼 Kamen Raidā Zanki, "Masked Rider Slashing Demon") is one of the many Oni Kamen Riders in the Kamen Rider Series Kamen Rider Hibiki. He solely goes by the name Zanki (ザンキ) and abandoned his human name Zaoumaru Zaitsuhara (財津原 蔵王丸 Zaitsuhara Zaōmaru) upon becoming an Oni.
Zanki is the oldest of the four main Oni in the series. Being the seasoned vet, even Hibiki saw him as a superior, even though Hibiki had once trained Zanki in the use of Taiko-type Ongeki. Zanki was first mentioned in episode 5, after defeating the Douji of a Bakegani, Todoroki and himself were forced to retreat after being attacked suddenly by the Bakegani itself. During their first on screen battle during episode 14, Zanki literally falls to his knees in pain as he battles a Douji/Hime with Todoroki. Due to his age and his wounds, Zanki is no longer able to fully engage Makamou in battle. Later on Zanki says that his time to retire has come and that Todoroki is to take the mantle of Zanki. Todoroki resists and says that he wants to make his own name, thus allowing Zanki to keep his Oni name. Over the next few episodes, Zanki has some apprehension to the way Todoroki battles Makamou. At first he sees Todoroki's style of cleansing the battlefield to not be traditional and as unneeded but eventually comes to understand that this is his student's way of fighting Makamou and that all Oni have their own way of doing so.
Later on, Todoroki begins to fall to fatigue in battle due to not having a supporter. Both Hibiki and Ibuki have Kasumi and Akira to help them with Disc Animal operation yet Todoroki is alone on his missions. Todoroki's fatigue begins to show in his battles and he becomes sloppy with the way he battles Makamou. Eventually Zanki decides that he will take on the role of a supporter for Todoroki and help guide him as Todoroki feels that he still needs the help of Zanki to be a great Oni warrior on his own.
During the middle of the series, Zanki's mentor, Shuki, returns and steals Todoroki's Henshin Onsa Onkaku and once again transforms into her Oni form. Zanki has a troubled past with Shuki, as she would go to great lengths to destroy all Makamou as they were the cause of her family's death. This was the only reason Shuki became an Oni and meant that she was not a pure Oni. As a young Oni, Zanki was caught in the mouth of the Notsugo that murdered her family, Shuki aimed her attack straight into Zanki's chest, hoping to kill the Makamou. Both Zanki and the Makamou survived as Shuki missed at the last second, but the attack was the reason for Zanki's declining health over the course of the series. In the final battle of Notsugo, Shuki was caught in its mouth much like Zanki many years ago, despite Shuki's orders to attack the Makamou with her in its mouth, Zanki would not attack his former teacher despite his contempt for her. Shuki then committed suicide as she aimed her weapon at herself, wounding the monster for an enraged Zanki to finish off. Zanki would go on to bury his teacher in a garden of flowers as her final wish for no one to see her true face.
In his final story arc, Zanki once again became an Oni, despite being told by his doctor that going into any more battles would result in Zanki shortening his life every time he transforms. During a battle where Todoroki was left immobile, Zanki had to step in to fill his spot. The night before his death, Zanki used a forbidden spell Shuki taught him on his soul that would not let it leave the mortal realm until his mission was fulfilled. However this same spell would result in the decay of his human soul should he remain among the living for too long. During a battle with a group of Makamou, Zanki was killed in an ambush by a pack of Bakeneko taking advantage while he left himself open for attack. Ibuki found his naked body and realized that Zanki was dead when he felt no pulse. Despite this, Zanki appeared in Todoroki's hospital room that night to comfort his student. Over the course of the next few days, Zanki helped Todoroki regain the ability to walk and finally transform again. In his last battle, Zanki was joined by Todoroki as the two battle a Kaengumo and pack of Bakeneko. At the end of this battle, Zanki and Todoroki cleansed the battlefield in Todoroki's style. As Todoroki bowed to his master, Zanki disappeared, his mission of seeing his greatest student become independent fulfilled, Zanki's soul could now rest in peace.
OOO, Den-O, All Riders: Let's Go Kamen Riders
Kamen Rider Zanki was part of a group of reinforcement riders led by Akira Date/Kamen Rider Birth to aid the primary riders in defeating the Rock Great Leader. All the Kamen Riders got on their bikes and performed the All Rider Break attack which destroyed the Great Leader.
- Rider Height: 220cm
- Rider Weight: 161kg
- Punching Power: 70t (Basic Form); 40t (Weakened Zanki)
- Kicking Power: 80t (Basic Form); 9t (Weakened Zanki)
- Maximum Jump Height: 100m (Basic Form); 40m (Weakened Zanki)
- Maximum Running Speed: 100m/3.5s (Basic Form); 100m/8.4s (Weakened Zanki)
- Finisher Power: 90t (Basic Form); 20t (Weakened Zanki)
In this Oni form, Zanki is a bronze demon that looks like Todoroki. To become this form, Zanki simply needs to pluck his brace strings, the vibrations from the strings cause his body to be hit by massive lightning bolts, changing him into his Oni form. Zanki also gains a second "oni face" which is a crest that forms on his forehead. Unlike most Kamen Riders, Zanki does not wear a suit, rather his demon form is his true form.
Appearances: Episodes 15-16, 37-38, 43-45, Let's go Kamen Riders
- Henshin Kigen Onka: A bracelet-like transformation device.
- Ongekishin Zantetsu: A device that attaches on his belt for uses of finisher attacks.
- Ongekishin Raigou: Todoroki's device, at first, it is owned by Zanki.
- Disk Animals: Zanki's disk-like support robots.
- Ongekishingen Retsuzan: A guitar-like weapon.
- Ongekigen Retsurai: Todoroki's weapon, at first, it is owned by Zanki.
- Raijin Make: Zanki's Rider Machine
- Kitōjutsu: Raigekiken (鬼闘術・雷撃拳 Demon Fighting Technique: Lightning Strike Fist): Charging himself with power, Zanki does an electric-powered punch that paralyzes all organs of any Makamou he is in battle with.
- Kitōjutsu: Onizume (鬼闘術・鬼爪 Demon Fighting Technique: Demon Claw): Forms claws from his hands to stab and slash at Makamou.
Ongeki Zan: Raiden Zanshin (音撃斬・雷電斬震 Sound Attack Slash: Thunderbolt Beheading Quake): Zanki stabs his weapon into the body of a large Makamou and changes is into its guitar form. He begins playing the guitar as fast as he can, causing electricity to flow from his body into the body of the Makamou, slowly causing its organs to expand and eventually explode.