Space Alloy Gren (宇宙合金グレン Uchuu Gokin Gren) is a special alloy made on Planet Fleed and was used for the construction and naming of the Grendizer. It features properties quite similar to the Super Alloy Z and its derivatives on Earth, as such the material is often used for repairing Grendizer as Gren is not found on Earth.
Among the metals found on the technologically advanced Planet Fleed, Space Alloy Gren is the hardest material found on the planet making the Grendizer very strong and durable. It is able to withstand extremely hot temperatures allowing it to reenter the atmosphere with little damage. Its name suggests that the metal is made in the low gravity of space to allow more control over its malleability during construction.