Kamen Rider Amazon

Amazon, a wild youth in the jungle, is remodeled by the ancient Inca science. With the "Bracelet of Gigi," the key that opens the door to the hidden treasure, on his arm, he protects the treasured ordnance and weaponry, as well as the future of mankind! The enemy is Gorgoth, a ten-faced demon who plans to conquer the world with the "Bracelet of Gaga," an opposing key!

(Source: MangaDex)