Ryūki

is a worshipper of Jashin.

Background
Ryūki dislikes the peace that spread throughout the world after the end of the Fourth Shinobi World War, as he feels it makes the countries and its people weak. To rectify this, he decided to follow in Hidan's footsteps by becoming immortal, and with that immortality, he would bring death and destruction back to the world and establish himself as its ruler. In order for Jashin to grant him immortality, he needed to acquire a large number of sacrifices. To that end, he and his fellow Jashinists began abducting young girls travelling through the mountains of the Land of Hot Water, luring them in by claiming to let them see their deceased loved ones.

Personality
Ryūki hates the current foundations in the shinobi world, seeking to turn them over and rule the world. He is obsessed with immortality and, believing that he received it, Ryūki, under a hail of weapons flying from the ceiling, rushed towards the enemy, shouting that he was immortal and the weapons would not harm him. Even when arrested and bound, he deliriously repeated about his immortality. He has great respect for Hidan and is loyal to Jashin, not allowing Mirai to speak ill of them. He claims to be the second coming of Hidan and believes that if he lived at the same time as him, they would fight shoulder to shoulder. Ryūki is very sadistic as he enjoyed hurting Mirai and Tatsumi and is also completely shameless, seeing nothing wrong with kidnapping and deceiving young girls.

Appearance
Ryūki is a tall and very thin man with protruding bones. He has short blond hair which spikes up on the sides, and a couple of strands falling over his forehead. He has red eyes that are deeply sunken and an earring in his left ear. He wears a long dark cloak with a high collar and the kanji for emblazoned on the back, along with pants and sandals. His left arm has been replaced with a prosthesis.

Abilities
As a follower of Jashin's cult, Ryūki has access to forbidden blood-related techniques such as Curse Technique: Body Controlling Manipulated Blood, allowing him to inflict injuries through a puppet once a connection is established. He displayed some leadership qualities, as he leads a whole group of people who treat him very respectfully. He is also a good strategist, as he developed a whole plan to lure the girls needed to perform the ritual of immortality. Despite this, he proved to be quite susceptible to genjutsu, easily falling into Mirai's trap, and was also unable to dodge the kunai that Kakashi threw at him, causing him to be injured in the arm.

Bukijutsu
Ryūki wields a large double-bladed scythe, much like Hidan's weapon. He is quite deft with it, using it to extract blood. Ryūki also has a large number of spear-like weapons at his disposal, which he uses in traps on the ceiling of the cave. If necessary, these spears begin to rain down on the opponent. Ryūki used such a spear when trying to kill Mirai. These spears, like the scythe, are similar to the weapons used by Hidan. Ryūki's group also used a poison on the kidnapped girls, making them susceptible to suggestion.

Konoha Shinden: Steam Ninja Scrolls
Ryūki meets Tatsumi, a young woman who dearly wishes to talk to her recently deceased mother. Because he has almost acquired the number of sacrifices he'll need, he asks Tatsumi to bring him one more follower in exchange for reuniting her with her mother's spirit. Tatsumi complies and brings her Mirai Sarutobi. Eager to begin making sacrifices to Jashin, Ryūki offers some drugged water to Mirai to drink. She suspects his intentions and refuses. When the other Jashinists attempt to seize her, Mirai reveals herself as a ninja of Konohagakure.

Mirai accuses Ryūki of being behind the recent kidnappings in the area, which he doesn't deny. Tatsumi is horrified to hear this, but he assures her that he will follow through on his promise to reunite her with her mother; he then moves to kill her so that they can meet in the afterlife. Mirai saves Tatsumi but is seemingly injured in the process. Ryūki doesn't think Mirai will offer much challenge but is proven wrong when she starts fighting and defeating the other Jashinists. He tries to make her stop by having the Jashinists take the other sacrifices as hostages, but they are stopped by Might Guy and Kakashi Hatake.

Although he doesn't want to because it will delay his plans for immortality, Ryūki calls upon Jashin via Curse Technique: Body Controlling Manipulated Blood: he ingests some of the blood Mirai spilt earlier, linking her with a puppet he has in his possession. When he stabs the puppet in the heart, Mirai is seemingly killed. And then she gets up, revealing to Ryūki that what he thought was her blood was only iron-rich hotspring water that she made appear red using a genjutsu. With his last resort having failed, Ryūki can only watch helplessly as Mirai defeats him with Wind Release: Whirlwind Fist. Ryūki and his followers are then turned over to Yugakure.

Trivia

 * The first kanji in Ryūki's name (龍) stands for ryūō, the promoted rook in shōgi, otherwise known as the dragon. This is similar to Hidan, whose first kanji means rook. This is pointed out by Kakashi when Ryūki is defeated.