Arata Kagami/Zi-O

In 2006, Arata Kagami (加賀美 新) was Kamen Rider Gatack (仮面ライダーガタック).

In 2019, the Kabuto Zecter comes to Arata's aid and allows him to briefly become Kamen Rider Kabuto (仮面ライダーカブト) before Kabuto's powers are used to create the Kabuto Ridewatch.

2006: Next Level Kabuto
In 2019, Arata is still working as a member of ZECT. He's on the mission to defeat a Worm who has copied the appearance of Shun Kageyama. He encounters Sougo Tokiwa in battle with a swarm of Worms and assists him as Kamen Rider Gatack. Then, Shun appears and they fight in Clock Up mode. After Shun is knocked out by Zi-O II, Another Kabuto, who is also revealed to be Sou Yaguruma, intervenes and the two escapes the scene. Arata explains about ZECT and his mission to Sougo and Woz, then leaves in confusion because the supposedly destroyed Shibuya district is thriving. Some time later, Arata is lured out by Shun for Yaguruma. He battles PunchHopper as Woz GingaFinaly battles Another Kabuto. He is subsequently captured by the mimicked Kageyama.

2019: The Chosen Kabuto
Somewhere, Kagami is being held hostage. The mimicked Kageyama only agrees to release him if the Riders give him the Ginga and Fourze Ridewatches, as he wants the meteorite carrying his Worm comrades to crash into Earth without fail. However, Sougo and Woz manage to free Kagami and prepare to fight. Kagami transforms into Gatack and charges at Kageyama, only to be stopped by Yaguruma as Another Kabuto. Being outnumbered 2 to 1, Gatack is soundly defeated by Another Kabuto and PunchHopper. PunchHopper would go on to take the Fourze and Ginga Ridewatches as he flees with Another Kabuto.

Back at Sougo's place, Kagami blames himself for the loss of the two Ridewatches, but Sougo says it's not anyone's fault. Kagami later admits to Sougo that he has never been the Kabuto Zecter's chosen one, and that he has never been able to defeat Kabuto. Sougo assures him that he is a strong warrior, and that if he becomes a King, he would like to have Kagami to fight alongside him and protect everyone. Kagami is amused, saying that even Tendou does not mention something like that.

On the rooftop of a building, Geiz and Woz are fighting Another Kabuto and PunchHopper. Four combatants use their respective finishing attacks and force one another out of their transformations. Kagami, Sougo and Tsukuyomi (who has just retrieved the stolen Ridewatches), arrive at the scene to help. As Sougo and Woz go into space to deal with the meteorite, Geiz and Kagami stay to fight PunchHopper and KickHopper.

KickHopper is defeated by Gatack in a clash of Rider Kicks. However, when he changes into Another Kabuto, he swiftly turn the table and knocks Gatack out of his transformation by his own Rider Kick. Kagami stands up, refusing to give in, declaring himself as the "deity of war". Suddenly, the Kabuto Zecter appears from the sky and Kagami is able to catch it. Seeing that the Zecter has finally accepted him as its user, he transforms into Kamen Rider Kabuto to fight Another Kabuto. Both fighters turn on ClockUp, but Kabuto quickly gains the upper hand. As Geiz Revive Shippuu has just finished off PunchHopper, Kabuto defeats Another Kabuto with a Rider Kick, destroying the Kabuto Anotherwatch as a result.

After the battle, the Kabuto Zecter in Kagami's hand turns into the Kabuto Ridewatch. He gives it to Sougo, saying that Sougo is going to need it in order to become a King.

Forms
Kagami was chosen by Gatack Zecter and became Kamen Rider Gatack. In 2019, he was chosen by the Kabuto Zecter and became Kamen Rider Kabuto.

Device

 * Gatack Zecter - Transformation device for Gatack
 * Rider Belt - Transformation Belt for Gatack
 * Kabuto Zecter - Transformation device for Kabuto

Weapons

 * Gatack Vulcan - Gatack's personal weapons in Masked Form
 * Gatack Double Calibur - Gatack's personal weapons in Rider Form

Portrayal
Arata Kagami is portrayed by Yuuki Sato (佐藤 祐基). As Kamen Riders Gatack and Kabuto, his suit actor was Yuji Nakata (中田 裕士).

Appearances

 * Icon-zi-o.png Kamen Rider Zi-O
 * Episode 37: 2006: Next Level Kabuto
 * Episode 38: 2019: Kabuto's Choice