As Tsukasa is fighting against Kaixa in another dimension, the Beetle Fangire defeats Wataru and becomes the new Fangire king, claiming Kivat. After the new King dissolves the truce, Yusuke arrives to protect Wataru before the boy runs off. After Yusuke expresses his reasons for helping the dethroned boy, Wataru takes refuge in the Hikari Studio. After being caught up on current events, Tsukasa makes his way to Castle Doran to save Yusuke as the Beetle Fangire absorbs the Arms Monsters into himself. After destroying the Swallowtail Fangire, Decade encounters the Beetle Fangire, who assumes Kiva's DoGaBaKi Form. When their fight makes its way to Yusuke and Wataru, the boy finds his courage to overcome his Fangire impulses and declares himself the King once more. He takes back the Kiva power and helps Decade battle the Beetle Fangire, mortally wounding him with a Darkness Moon Break/Dimension Kick combo. Later, Tsukasa pays a final visit to the Kurenai manor to play a final song for the dying Beetle Fangire, whom he knew was the man he met earlier and is Wataru's father. Soon after, as Yusuke moves into the Hikari Studio with Kiva-la sneaking in, the group prepares to enter yet another world.
Recap / Kamen Rider Decade Ep 5 The Biting Kings Qualifications