Kamen Rider Dark Kiva
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.
Taiga Nobori (登 太牙 Nobori Taiga?) was born prior to 1986 as the first-born son of Maya, the Queen of the Checkmate Four, and the original King. He would receive the title of King at infancy after his father's death before he was spirited away by Maya to be raised by Mamoru Shima as a human child. He wears a glove over his hand to conceal his Checkmate Four crest. After learning of his true nature as the Fangire offspring of the previous King and Queen of the Checkmate Four, Taiga developed a disdain for humans as he intends to prevent the progress of humanity from moving forward to the point of becoming a problem for Fangires like with Ixa. His meeting with Wataru and taking his title as the Fangire King, as well as his eventual downward spiral, forces Taiga to knock out Maya to take the power of Dark Kiva as his own and reclaim his birthright. He would use the Dark Kiva power to settle things with Wataru once and for all, but in the end, he relents and uses the power to fight the revived Bat Fangire. The Dark Kiva powers would stay with Taiga after the final battle was over.
Kamen Rider Dark Kiva
Dark Kiva only appears to have one form, similar to that of Kiva Emperor Form in black and red. However, Dark Kiva does not require the use of a being such as Tatsulot to achieve this form, and has no chains on his body as Kiva needs to control his power. As Dark Kiva, the user has access to an unlimited potential of power that is hindered within its successor such as telekinesis and the use of the Kiva insignia as a weapon.
As Maya would later explain, the Kiva power cannot be used by a normal human, as usage would ultimately result in death. This would prove to be true, as Otoya had used the Dark Kiva power a total of three times before finally dying due to the strain it put on his body. Shima also mentioned this when Wataru revealed his heritage to him.
Dark Kivat Belt
The Dark Kivat Belt (ダークキバットベルト Dāku Kibatto Beruto?) is a means of transforming into Dark Kiva. Similar to how Kiva transforms, it has Kivat-bat the 2nd bite the user, and then perch upside down on the Power Roost (パワールースト Pawā Rūsuto?) of the belt's Dark Kibuckle (ダークキバックル Dāku Kibakkuru?) to complete the transformation, separating from the belt when certain conditions demand for it like Fuestle-blowing. The Dark Kivat Belt also has six Fueslots to hold the six Fuestles.
Like Kiva, Dark Kiva accesses its arsenal through whistles on its belt called Fuestles (フエッスル Fuessuru?), which he gives to Kivat the 2nd to blow into to evoke a power-up. Compared to Kiva's Fuestles, his predecessor's emit at a lower pitch similar to a pipe organ.
- Dark Wake Up (ダークウエイクアップ Dāku Ueiku Appu?): The Dark Wake Up Fuestle allows Dark Kiva to perform one of three finishing moves depending on the frequency.
- Darkness Hell Crash (ダークネスヘルクラッシュ Dākunesu Heru Kurasshu?): Referred to by Kivat-Bat the 2nd as "Wake Up One," the Darkness Hell Crash is a punch with the force of 65t. When performed, day turns into night with blood red fog. Dark Kiva then does a flying punch with his right arm. This Dark Kiva's Rider Punch.
- King's Burst End (キングスバーストエンド Kingusu Bāsuto Endo?): Referred to by Kivat-Bat the 2nd as "Wake Up Two," the King's Burst End is an Emperor Moon Break-style Rider Kick with the force of 180t and green energy blades.
- King's World End (キングスワールドエンド Kingusu Wārudo Endo?): Referred to by Kivat-Bat the 2nd as "Wake Up Three," a self-destructing attack with an unknown level of destructive power. As the name implies, it could destroy everyone nearby. However, it was never used.
- Garulu-Seal (ガルルシール Garuru Shīru?): This Fuestle seals Garulu by emitting a continuous sound, creating an energy sphere that captures Garulu and converts him into the Garulu Saber.
- Basshaa-Seal (バッシャーシール Basshā Shīru?): This Fuestle seals Basshaa by emitting a continuous sound, creating an energy sphere that captures Basshaa and converts him into the Basshaa Magnum.
- Dogga-Seal (ドッガシール Dogga Shīru?): This Fuestle seals Dogga by emitting a continuous sound, creating an energy sphere that captures Dogga and converts him into the Dogga Hammer.
- Doran (ドラン?): This Fuestle summons Castle Doran. However it was never used.
- Buroon (ブロン Buron?): This Fuestle summons Buroon from Castle Doran. However it was never used.
The Zanvat Sword (ザンバットソード Zanbatto Sōdo?) was a sword of great power crafted and used by the King. However, in a fit of rage, he tossed the weapon into Castle Doran's wall to prove he did not love Maya. The weapon remained there until it reacted to Wataru in 2008.
The Jacorder (ジャコーダー Jakōdā?) is an item that is inserted into Sagarc to evoke the transformation into Saga. When Taiga inherits the power of Dark Kiva, he continues to use the Jacorder as his primary weapon, along with its Snaking Death Break finishing attack.
Castle Doran (キャッスルドラン Kyassuru Doran?) is the King's base of operations which is of the Doran Race (ドラン族 Doran Zoku?). Though originally called the Great Wyvern (グレートワイバーン Gurēto Waibān?), the Fangires captured it and bonded it to the mold of a castle so it would serve as the base of the Checkmate Four within the forest of the Fangires. After the King's death in 1986, it would become masterless until Wataru, through Kivat, inherited it from his mother Maya.
- "TV Asahi's page for Kamen Rider Dark Kiva". Retrieved 2009-06-27.
- "TV Asahi's page for the Zanvat Sword". Retrieved 2009-06-27.
- "東映ヒーローネット | special fanclub toeihero.net | 皇帝の大剣". Retrieved 2008-09-26.
- "TV Asahi's page for the Sagarc Belt and the Jacorder". Retrieved 2009-06-27.
- "TV Asahi's page for Castle Doran". Retrieved 2009-06-27.