1986
The Checkmate Four's original King (キング, Kingu?, portrayed by Shinya Niiro) is referred to as the Dark Kiva (闇のキバ, Yami no Kiba?), the lord of all Fangires and the original Kiva who was a threat to humanity in his time. Despite being married to the previous Queen of the Checkmate Four, Maya, he has no actual love for her as her purpose to him was the birth of his son, Taiga Nobori. Due to Wataru Kurenai's actions in 1986, the King loses the powers of Dark Kiva to Otoya Kurenai. Otoya would use this power to battle against him alongside the time-traveling Wataru as Kiva Emperor Form, ultimately weakening the King enough that Taiga redirected his attack and destroyed him. The use of the Dark Kiva power would ultimately cost Otoya his life.
Read more about this topic: Kamen Rider Dark Kiva