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Icon-fourze.png This article is about a/an movie-exclusive villain in Kamen Rider Fourze.

Skydain (スカイダイン Sukaidain) was the red jet-like younger sister of the Kyodain. Like her brother, she gains her own personality and wants to rebel against humanity. As Kyodain's human identity, Shizuka Shiroyama (白山 静 Shiroyama Shizuka) is Saeba's personal secretary.


Skydain, Groundain, and Black Knight were created by Professor Blink; but the Kyodain went rogue and attacked the professor. The professor proceeded to seal their power in the satellite they were in, forcing the Kyodain to assume weak human forms.

Under the guise of the clumsy assistant to Harumi Saeba (her brother's guise), Shizuka Shiroyama of OSTO Legacy, Skydain plotted with her brother to use the Kamen Rider Club to regain their powers and take over XVII. When their plan succeeded, the Kyodain began their genocide attack with XVII but Kamen Rider Fourze Cosmicstates managed to foil the plot with his warp drive ability.

Enraged, the Kyodain fought him and Kamen Rider Meteor. While at first having the advantage, Fourze gained the Fusion Switch and after a long battle destroyed them with the States' Limit Break.

Super Hero Taisen Z

Skydain revived as a member of Space Shocker.

The Kyodain are later revived as members of Space Shocker. However, due to their sense of honor and desire to fight GavanIcon-crosswiki.png, the two are destroyed by Space Ikadevil for acting against their cause. Kamen Rider × Super Sentai × Space Sheriff: Super Hero Taisen Z




  • Height: 228 cm.
  • Weight: 209 kg.

Skydain is armed with built-in blades in her arms. She is quicker and more agile than her brother.



The Union State of Grouncar and Skyjet

  • Height:
  • Weight:

Skydain is also able to transform into a jet-like form called the Skyjet (スカイジェット Sukaijetto). In this form, she can combined with Groundain.

Behind the scenes


Shizuka Shiroyama/Skydain is portrayed/voiced by Ayumi Kinoshita (木下 あゆ美 Kinoshita Ayumi), who previously portrayed Marika "Jasmine" Reimon/Deka YellowIcon-crosswiki.png in Tokusou Sentai DekarangerIcon-crosswiki.png.

Concept Art

Skydain was designed by Kia Asamiya (麻宮 騎亜 Asamiya Ki'a).


  • Skydain is an homage to SkyzelIcon-crosswiki.png from Space Ironmen KyodainIcon-crosswiki.png.
    • However, unlike the original Skyzel who is a male and older brother, Skydain is a female and younger sister.


Icon-fourze.png Kamen Rider Fourze
Kamen Riders
Gentaro Kisaragi - Ryusei Sakuta - Nadeshiko Misaki - Kamen Rider Ikaros - Boot
Fourze Driver - Meteor Driver- Nadeshiko Driver - Astroswitches - Astroswitch Case - Billy the Rod - Hee-Hackgun - NS-MagPhone - Meteor Galaxy - Barizun Sword - Meteor Storm Shaft - Machine Massigler - Machine Meteorstar - Powerdizer
Kamen Rider Club
Initial Members
Yuki Jojima - Kengo Utahoshi - Miu Kazashiro - Shun Daimonji - Tomoko Nozama - JK - Chuta Ohsugi - Ran Kuroki - Haru Kusao
5 Years After
Saburo Kazeta - Rumi Komaki - Daita Kondou - Chikao Nezu - Miyoko Ohki
Ishinomori Characters
Inazuman - XVII - Skydain - Groundain - Black Knight - Inga Blink
The Horoscopes: Sagittarius - Virgo - Leo - Libra - Scorpio - Cancer - Aries - Capricorn - Aquarius - Taurus - Gemini - Pisces

Zodiarts: Orion - Chameleon - Unicorn - Hound - Altar - Pyxis - Perseus - Lynx - Dragon - Pegasus - Cygnus - Coma - Musca - Hercules - Lepus

Stardust Ninja Dustards
Foundation X
Lem Kannagi - Katal - Solaris - Chancellor Kiima - Suddendath Beta
Xatan - Eel - Gahra