Arriving in the World of Kiva, Tsukasa and company discover that the Fangires of this world have made a truce with the humans. However, when Tsukasa finds the Lion Fangire attacking a young woman, he transforms into Decade to fight him. Wataru, the King of the Fangire Race, witnessed this and becomes Kamen Rider Kiva to fight him with the aid of his Arms Monsters, forcing Decade to assume Kamen Rider Kuuga's Mighty, Titan, and Dragon Forms to counter. Yusuke managed to stop the fight, and the Swallowtail Fangire revealed that the young woman was actually a renegade Fangire. Yusuke revealed he had promised to help Wataru because he was uncomfortable with being the King. After meeting a mysterious man who was disgusted with the human/Fangire treaty, Tsukasa later encountered Kiva-la, who use