Kamen Rider Kiva / Fangire / Checkmate Four

Maya / Pearlshell Fangire
Maya is the human form of the Pearlshell Fangire and the original Queen of the Checkmate Four in 1986, possessing the Queen tattoo on her palm. Her powers are similar to Kiva as she can turn day into night with a blood red moon in the background and teleport in black rose petals as well as being the strongest of the Checkmate Four and consort to the King, giving birth to Taiga Nobori. Due to her status, Maya is in charge of executing any Fangire who betrays their kind, accompanied by Kivat-bat the 2nd. She lived for centuries, meeting Antonio Stradivari and Antonio Vivaldi and becoming their pupil, gaining an admiration for their genius and a love for human art. After Vivaldi's death, Maya found no other human like him until she crosses paths with Otoya, questioning her mission and the concept of love. As a result, while accompanying Otoya while he lost his memory, she starts to question humanity. Eventually, Maya is forced to reveal her true identity as a Fangire to Otoya when attacked by Dogga. But when Otoya refuses to kill her, she asks him to let her help him into creating an ideal violin for him to show his true potential, which would be named the Bloody Rose. However, in spite of Otoya telling her that they can never meet again, Maya falls in love with Otoya instead of her initial intent to kill him. This is expressed when Otoya and the King face off and later when she assaults Dark Kiva to hold him while Yuri escapes with Otoya, resulting with Maya being stripped of her title, rank, and powers as the Queen. Soon after the death of the original King, Maya stays by Otoya's side in his final moments.

Maya eventually gave birth to Wataru, leaving him as a child in order to protect him from retribution, telling him to become strong. Maya is eventually exiled to a location only the Bishop knows of, to keep her safe from the other Fangires that would intend to kill her as only she can bestow Kivat-Bat the 2nd's power to another. By 2008, now wearing an eye patch, Maya is found by her successor Mio, explaining to her how succession works along with realizing that Mio is following a path similar to her own. Taiga later visits his mother to learn the truth, bringing Wataru to meet her, again, despite her wishes. After being knocked out by a distraught Taiga who takes Kivat-Bat the 2nd as his own and claiming to have killed her, Maya reveals herself and expresses her pride in her sons finally working together.

Rook / Lion Fangire
The Rook, named after the Rook tattoo on his hand, is the human form of the Lion Fangire and a member of the Checkmate Four. The Rook is the one Yuri swore vengeance on for murdering her mother, as well as being the one who slaughtered nearly the entire Wolfen Race. Being one annoyed with boredom, the Rook devised his own personal game: the "Time Play". In a Time Play, he feeds on a select group of people within a time limit, with failure to make the intended number resulting in self-punishment with an electric shock strong enough to kill a human. However if he manages to succeed the right amount of victims within his game, he rewards himself with ice cream. Eventually he is defeated by Yuri when she tricks him into using the Ixa System to weaken him before Otoya and the Arms Monsters further weaken him for Yuri to deliver the deathblow with the Ixa System. However, the Rook barely escapes with a severe wound on his right shoulder, entering a deep rest to recuperate from his injuries. By 2008, the Rook has lost his memories while resting and possesses a child-like mentality, found by Wataru and Shizuka. Because he cannot remember his name, they call him Dai-chan (great) due to his size. Soon after, Dai-Chan regains all of his memories as the Rook upon seeing one of his old battlefields. However, the Rook becomes bored with his Time Plays and now resorts to playing the ultimate game, doing good deeds before getting himself killed to enter the pearly gates. This plan is changed when the Rook seeks to destroy Ixa, eventually being destroyed by Megumi as Ixa attacking his shoulder. he Rook later resurfaces to commit good deeds in a game to get to heaven, found by Megumi as she eventually kills him by targeting the weak point her mother made on him.

Bishop / Swallowtail Fangire
The Bishop is the human form of the Swallowtail Fangire whose task as member of the Checkmate Four is to oversee the progress of all Fangires and their moral conduct, deeming those who are traitors to their aboslute laws such as having relations with humans. The Bishop can shoot blue flames from his hand while in human form. In 1986, as the previous King's right hand, he oversees Taiga's development while not leaving Castle Doran to carry out his mission, even reporting to the King of Maya's actions. In 2008, he appears before Mio to have her embrace her destiny as the new Queen before searching for Taiga to complete the Checkmate Four prior to the Rook's demise, deeming Taiga as a better King than the last one. However, since learning that Kiva is Wataru, the Bishop feels that he would cause another disruption in the Fangire hierarchy as his father had in the past. His fears come true when Mio attempts to kill Taiga so Wataru could be the new King. After proudly admitting that he had to kill her for it, letting Wataru believe he was responsible in order to rid their kind of him, the Bishop is forced to run for his life from a furious Taiga when Taiga tries to kill him. The Bishop then sees Taiga unfit to bear the title of King and he swears to make him pay for turning on him by gathering a massive amount of Life Energy to set up a takeover. He resurrecting an army of Fangires to gather Life Energy in order to resurrect the previous King to take Taiga's place, using his own soul after a mortal wound from Rising Ixa to become one with the previous King.

King / Bat Fangire
The Bat Fangire is the previous King of the Checkmate Four, who is also known as the first Dark Kiva, the lord of all Fangires and the original Kiva who was a threat to humanity in his time. In spite of being married to Maya, he has no actual love for her as her purpose to him was the birth of his son, Taiga Nobori. However, the King disapproves Maya's sudden association with a human. In 1986, he usually assuming the Bat Fangire form when he cannot transform into Dark Kiva. But after Otoya assumes the mantle of Kiva, King assumes his Fangire form to battle him. He would eventually be defeated at the hands of Otoya when he took the power of Kiva from him, attempting to kill Taiga in act of vengeful rage.

In the end, the King is severely weakened by the teamwork of both Kiva and Dark Kiva and has his title transferred to the young Taiga after the infant indirectly kills him by deflecting his attack, also saving Maya's life. However, he is fatally wounded when his son turned his attack against him, realizing that Taiga has now succeeded him and vowed that he would avenge him in his final breath. Though Taiga succeeds him as the new Fangire King after his death, the King's power as Kiva is inherited by Wataru. In the present day, Bishop manages to resurrect the previous King, though in a more demonic version of his Fangire form without a conscious mind who is motivated to kill those bearing his title. Although the Bat Fangire had overpowered both Kiva and Dark Kiva, the two Riders successfully destroyed him by teamwork.

Mio / Pearlshell Fangire