Kugai Kudo

Kugai Kudo (狗道 供界) is a former researcher in Yggdrasill Corporation who transforms into Kamen Rider Saver (仮面ライダーセイヴァー). His only appearance was in Kamen Rider Gaim Gaiden: Kamen Rider Duke.

History
Kugai was the predecessor of Ryoma Sengoku in the Yggdrasill Laboratory for Lockseeds. Ordered by Amagi Kureshima to test out his subordinate, Ryoma Sengoku's first functional Lockseed. Kugai was killed during the test and his body was destroyed.

Kugai managed to enter Limbo, aware of the world and managed to gain a physical appearance due to the Sengoku Driver he was equipped with. Kugai also managed to keep the Zakuro Lockseed after his death and facilitated his own mass production laboratory with data stolen from Yggdrasill, creating blank pomegranate Zakuro Lockseeds that explodes upon activation.

Intentionally making his actions aware to Yggdrasill, he taunts Ryoma Sengoku, proclaiming that he can guide him to the path of God alongside him, testing him to overcome his labors. Due to Sid's interference to stop brainwashed members of Black Bodhi and acquiring one of the blank Lockseeds, Ryoma and Takatora track his location, discovering his artificial Helheim factory.

Kugai demonstrates to Ryoma that he is the final task he must overcome, utilizing a Genesis Core Unit as an extension of his Sengoku Driver with his Zakuro Lockseed modified to summon a variant of the Sonic Arrow called the Saver Arrow. Initially gaining the upperhand, fighting Duke and Zangetsu as he can overpower them one on one, he is defeated by their combined efforts.

Days later, Ryoma finishes his Genesis Driver with the intent to destroy Kugai for good. Ryoma taunts Kugai saying that he is third rate and cannot be considered a potential person to acquire Godhood. During his second encounter, Ryoma damages his Sengoku Driver, causing Kugai to wallow in pain as the Driver is what maintains his physical form. Kugai dies when Ryoma shoots his Sengoku Driver directly.

Sometime after or before, Kugai meets with Shura in a blank space, with Shura becoming an affiliate of the now defunct Black Bodhi terrorist organization. Shura carries on Kugai's legacy, owning several Sengoku Drivers for himself and his fight club, and wishes to enact the Saver System, which will wipe out any unwanted humans who are not worthy.

Arms
Like his fellow Lockseed-using Armored Riders, Kamen Rider Saver's forms are called Arms (アームズ). His Sengoku Driver plays Japanese horagai music and announces "Ha!" (ハ!) before every transformation, while his personal Lockseeds are styled with a mix of Japanese words and English words.

By pressing the Sengoku Driver's Cutting Blade down on the Lockseed after transforming from one to three times, Saver can activate one of three finishing moves based on his current Arms form: Squash (スカッシュ), Au Lait (オーレ), or Sparking (スパーキング).

Devices

 * Sengoku Driver - Transformation device
 * Removable slots for additional Lockseeds:
 * Genesis Core - Essential to access a Jimber Arms
 * Lockseeds - Gives access to Saver's Arms changes, depending on which lock is used

Weapons

 * Arms Weapons - Weapons that come with the Arms:
 * Saver Arrow - Saver Blood Zakuro Arms' personal weapon through the Blood Zakuro Lockseed
 * Daidaimaru (Bujin Gaim ver.) - Saver Blood Zakuro Arms' personal weapon through the Blood Orange Lockseed

Etymology
The katakana used in Kamen Rider Saver, セイヴァー, can be romanized as both Saver and Savior. The latter is mostly used in many localization and translations and ties in better with the character of Kugai as as he views himself as a Messiah, with the Lockseed No. on the Zakuro Lockseed being "LS-MESSIAH".

Portrayal
Kugai Kudo is portrayed by Jun Toba (鳥羽 潤).

As Kamen Rider Saver, his suit actor is Yugo Fujii (藤井 祐伍).