Iron Cross Army
The Iron Cross Army are the main villains of the series. They are an alien army that has destroyed numerous galaxies in their path of conquest.
Professor Monster
The leader of the Iron Cross Army. He was responsible for the destruction of Planet Spider and 400 years afterward, he seeks to conquer the Earth as well. The blood of other lifeforms serves as the source of his immortality. In the final episode, he enlarges himself and turns into "Big Monster", but is defeated by a single strike of Leopardon's "Sword Vicker" attack
Amazoness
The female commander of the Iron Cross Army. She is in charge of espionage and the planning of attacks. Has the ability to assume numerous disguises. From the beginning of the series, she assumes the identity of Saeko Yoshida, the editor of Weekly Woman magazine. After Spider-Man sees through Saeko's true identity, she disappears from her job and Weekly Woman is discontinued shortly afterward. Although she suspects that Takuya is really Spider-Man, she is unable to prove this without a doubt until the final episode. Her outfit changes throughout the course of the series: she wars a black leotard with her own natural hair for the first 18 episodes; a silver mini-skirt outfit and a red hairpiece for episodes 19 throughout 30 and 32; the same outfit but with a black hairpiece for episodes 31 and 33 to 38; and her original leotard outfit with a hairpiece for the final three episodes.
Bella and Rita
Two ancient female warriors from an uncharted region of the Amazon whose mummified bodies were resurrected by Professor Monster. Bella uses with a bow with poisonous arrows, while Rita wields a machine-gun.
Ninders
The foot soldiers of the Iron Cross Army. They disguise themselves as humans while conducting undercover missions in public, but are still identifiable by the exposed circuits behind their ears and their metallic hands.