Jiro

Jiro (次狼) is the human form of the violent and impulsive Garulu (ガルル), the strongest and last surviving member of the Wolfen Race (ウルフェン族) that were decimated by Rook in one of his Time Plays. He is also one of the IXA Belt users in 1986.

History
In the human guise of Jiro, Garulu sees the world as a place of utter corruption and usually prefers to be with Castle Doran as its lead caretaker. In 1986, Jiro is a regular at the Café mald'amour and attacked regulars in secret to feed on them. Recognizing Yuri as an "ideal wife" to revive the Wolfen Race through, Jiro joins the Fangire Hunters to get revenge on them and becomes the first user of the Ixa System, saving Yuri Aso from the Earwig Fangire and also alerting Otoya Kurenai to his true nature, with the two at odds with each other unless Yuri's in any danger. But after Yuri revealed that her heart was for Otoya, Jiro left a lost man after exposing himself for what he truly was and attempts to get his revenge on Rook. But after the attempt, Jiro was forced to ask for Otoya's help, with them, Ramon, Riki, and Yuri defeating a weakened Rook together.

Jiro, Ramon and Riki would soon encounter the Fangire King who easily defeats them. Fortunately for them, all three manages to escape his clutches. After unsuccessfully trying to kidnap Maya to act as a shield for them, the Fangire king appears in front of them again as he soundly beats all three once more. The Fangire King then offers them a choice between getting killed or killing Otoya themselves. After trying and finding themselves unwilling to kill Otoya (as per the King's offer), Jiro, Ramon and Riki decides to leave town.

However, Jiro comes back to unsuccessfully aid Otoya and Maya against Dark Kiva and gets sealed into the Garulu Saber for his efforts. He manages to escape imprisonment along with the other Arms Monsters because of Otoya and runs away after seeing Otoya and King fighting. In the fight's aftermath, before deciding to lead the Arms Monsters in keeping Castle Doran from running amok, Jiro questions Otoya's faith in them when Otoya suddenly appears to ask that he and the others protect Wataru in his stead. Though acting cynical, Jiro silently nodes to Otoya as he sees that his friend passed over. This leads to Jiro now aiding Wataru in 2008, his Garulu Saber form used by Kiva to assume Garulu Form. Out of the Arms Monsters, Jiro supports his current condition as Wataru's ally most as a token of respect for Otoya, even to the point of sometimes getting directly involved to honor his vows.

Den-O
Jiro and the other Arms Monsters are in 1932. Urataros possesses Jiro as Ramon/Ryutaros hogs the rice.

Personality
At first, Jiro was not much different from most of the Fangires that preyed on humans. He did, however find himself having an interest in Yuri and Susan Kumiko. He also likes coffee apparently. Although Jiro originally disliked Otoya and saw him as pathetic, he soon came to befriend and respect him when he saw all that Otoya has done for him and others. It seems that being with Otoya has changed Jiro for the better as he seemingly stopped killing humans as well as Otoya himself even when he was threatened by the Fangire King. After promising Otoya to take care of Wataru, Jiro developed a more serious attitude while helping Wataru become a better man. He does however, still have a comical side as he cried and somewhat freaked out at Nago and Megumi's wedding.

Net movies
In the The Queen of the Castle in the Demon World net spin-off movies, Jiro challenges Wataru to a card game when he accidentally ends up in Castle Doran, losing to him in Hell's Old Maid and suffers a humiliating punishment. He later tracks down Wataru to get back at him, finding Shizuka before she overwhelms his nose with an old fish and manhandles him for threatening Wataru.

Novel
In the novel reimagination of the TV series, Jiro/Garulu is a Fangire Hunter, while Bassha and Dogga, as well as Kivat do not exist in this story, as Kiva is Wataru's Fangire form.

Devices

 * Ixa Belt: Transformation belt
 * Ixa Knuckle: Transformation device
 * Fuestles: Whistle-like devices that activate a function, depending on the Fuestle.

Fuestles
There are three Fuestles (フエッスル) in the possession of Kamen Riders Kiva, Ixa and Dark Kiva respectively, which allow access to Garulu's power.
 * Garulu Fuestle (ガルルフエッスル): Kiva uses this Fuestle to summon Garulu from Castle Doran. This Fuestle is inherited by future Kamen Rider Kiva in 2031.
 * Garulu Fake Fuestle (ガルルフェイクフエッスル): A Fuestle that copies the frequency of Kiva's Garulu Fuestle, with the Ixa Belt announcing "Garulu Fake" as Ixa hijacks the Garulu Saber when it is summoned by Kiva.
 * Garulu-Seal Fuestle (ガルルシールフエッスル): This Fuestle seals Garulu by emitting a continuous sound, creating an energy sphere that captures Garulu and converts him into the Garulu Saber.

Rider Card
The power Garulu lends Kiva is harnessed in the Kiva Garulu (キバガルル) Form Ride Card (フォームライドカード), which is used by Decade to transform into Kamen Rider Kiva Garulu Form. Unlike Kiva himself, who is left-handed in this form, Tsukasa prefers his right hand. This card is first used in the World of Ryuki to fight Kamen Rider Knight and again in the World of Agito to fight Kamen Rider Exceed Gills.

Portrayal
Jiro is portrayed by Kenji Matsuda (松田 賢二), who previously portrayed Zaomaru Zaitsuhara (Kamen Rider Zanki) in Kamen Rider Hibiki. As Garulu, his suit actor was Seiji Takaiwa (高岩 成二). As Kamen Rider Ixa, his suit actor was Jiro Okamoto (岡元 次郎).

Etymology
While "garuru" (ガルル) is a Japanese onomatopoeic sound representation of a wolf's howl, the last syllable in Jiro's name contains the kanji for "wolf" (狼).