The Space Ironmen Kyodain siblings from space who plan on attacking the Earth.
- Groundain 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. Groundain is an homage to Grounzel from Space Ironmen Kyodain.
- Skydain 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.