Fire Agate is one of the Agates following under Holly Blue Agate's command on Aredox. She only makes a minor appearance within the special: My Little Universe: Anarchy.
History
Upon arriving into Aredox, Bismuth was assigned under Fire Agate's watch and command after being accepted to them by Holly Blue Agate herself.
Later on, she was assigned by Holly Blue to keep track of Bismuth, and to not let her out of Fire Agate's sight, after Bismuth was caught talking to Twilight Sparkle before hand.