Series: Kamen Rider Amazon
Ally of the original Kamen Riders. Motorbike specialist. He helps Amazon settle in Japan.
The nephew of professor Kosaka and Daisuke's first friend in Japan, helping him in anyway he can. In Episode 13, it is shown that Masahiko teaches Amazon to speak coherent Japanese. Masahiko attends Jonan Elementary School.
Mashahiko's big sister. At first she doesn't trust Amazon due to bringing Geddon to Japan and causing chaos. After being constantly rescued and helped by Amazon she puts her faith and trust in him.
A mole monster, nicknamed Mogura, able to burrow underground and prone to chant "chu-chu". Mogura originally was working for Geddon and was sent after Amazon only to fall back due to police interference. After getting a chance to redeem himself, Mogura goes after Masahiko to set a trap for Amazon which ended up with his arm dislocated and many other injuries before he escaped. As a result, Mogura gets exiled to the surface and chained up to die of sun stroke. Amazon, taking pity on the monster, rescues him from his cruel fate. Though confused why, Mogura becomes Amazon's recurring ally until Garanda's Tokyo Mold Destruction Operation, where he faked offering his services to Garanda to take mold. However, Kinoko expected it and poisoned Mogura, living long enough to make his way to the doctor, but too late to be saved by the newly developed antidote. Soon after avenging him, Amazon builds a memorial in Mogura's honor. Appeared in Episodes 5 to 20.
Chief of the Incas who bestowed the GiGi Armlet to Daisuke before he died.
He knew the nature of the Gigi Armlet and his nephew Masahiko become Daisuke's friend. He is murdered by the Kumo Beastman.
Yamamura is fatally wounded by the Akajusha as Yanamura reveals the GaGa Armlet and he has a daughter.