He is portrayed by Fumiya Takahashi.
When Aruto was young his father Soreo died. Soreo was replaced by a HumaGear doppleganger who sacrificed himself to protect Aruto from an explosion caused by the Daybreak Town incident.
As an adult, Aruto aspired to be a comedian but struggled due to not being able to tell funny jokes. After his grandfather died, he wrote in his will that Aruto was to be his successor as CEO of his company, Hiden Intelligence.
Though reluctant at first, Aruto accepts the role and becomes Zero-One to defend humanity from MetsubouJinrai.NET and their rogue HumaGears.
Kamen Rider X
Kamen Rider Amazon
Kamen Rider Super-1
Kamen Rider ZX
Kamen Rider Black/RX
Kamen Rider Kuuga