Robot Girls Team Z (Robot Girls Team Z EX in their upgraded state) is a team of three teenage girls adorned in battle suits based on the main super robots from the Mazinger franchise: Mazinger Z, Great Mazinger, and Grendizer that are made with special Super Alloy Z fibers (upgraded to Super Alloy New Z in episode 8) and powered by Photonic Energy. It was formed when Z-chan and her grandmother got themselves in a lot of debt and her grandmother was taken away. Getting a job at the Photon Power Laboratory, she worked alongside Gre-chan and Grenda-san to pay for the debt. Ever since, they have gotten jobs to promote the use of Photonic Energy while battling the forces of the evil such as Dr. Hell and the Mycenae Empire who seek to use it for world domination. Ironically, most of Team Z's battles with these villainous groups cause more mayhem and destruction than the groups do alone.
- Z-chan/Devil Scrander Z-chan (Team Leader, based on Mazinger Z)
- Gre-chan/G Booster Gre-chan (based on Great Mazinger)
- Grenda-san/Spazer Grenda-san (based on Grendizer)