|This article is about a/an group of villains in Kamen Rider Fourze.|
The evil Space Ironmen (宇宙鉄人 Uchū Tetsujin?) are Machine Organisms (機会生命体 Kikai Seimeitai?) infused with Cosmic Energy created by the Alicia Federation (アリシア連邦 Arishia Renpō?). The Kyodain (キョーダイン Kyōdain?) are the first two Space Ironmen created by the Alicia Federation who suddenly become activated and gain their own personalities. The Space Ironmen are an homage to the characters from the Space Ironmen Kyodain series, which was also created by Shotaro Ishinomori.
- Main article: Groundain
Groundain (グランダイン Gurandain?) is the blue car-like older brother of the Kyodain. To begin his act of treason against humanity, he rushes to complete the military satellite weapon: the XVII. He is armed with a powerful cannon built into his chest called the Grounbuster X (グランバスターX Guranbasutā Ekkusu?). Groundain is an homage to Grounzel from Space Ironmen Kyodain.
- Main article: Skydain
Skydain (スカイダイン Sukaidain?) is the red jet-like younger sister of the Kyodain. Like her brother, she gains her own personality and wants to rebel against humanity. She is armed with built-in blades in her arms. Skydain is an homage to Skyzel from Space Ironmen Kyodain.
- Main article: Black Knight
Black Knight (ブラックナイト Burakku Naito?) is the third Space Ironman created by the Alicia Federation who works alongside an agent from the Alicia Federation named Inga Blink. Unlike the Kyodain, Black Knight relies more on more defense than offensive attacks due to his strong armor. Black Knight is armed with a rapier called the Blackest Leaver (ブラッケスト・リーバー Burakkesuto Rībā?) and a machine gun built-in to his chest. Black Knight is an homage to the evil Black Knight of the Robot Army Corps from the Space Ironmen Kyodain series.
- Main article: XVII
XVII (エックスブイツー Ekkusu Bui Tsū?)is a large satellite weapon that has its own will known as the "Space Ironmen's Ultimate Form" (宇宙鉄人の究極体 Uchū Tetsujin no Kyūkyokutai?) which the Kyodain make it their goal to complete. The XVII is an homage to Daitetsujin 17, which was also created by Shotaro Ishinomori.
- Main article: Gunbase
The Gunbase (ガンベース Ganbēsu?) are small round drones part of XVII's defense system to guard the inside from intruders. The Gunbase are a homage to the support robot character Gonbesu from Space Ironmen Kyodain.