Muetta is a Efy Dolgh pilot.

Spoiler

She is a clone of Yukihime, grown using her DNA aboard an Efy Dolgh ship according to Efy Dolgh's attitude to create on-site its own troops by cloning conquered foes. Her Geoframe is designated "Medusa" by the U.N. She is stabbed by Mirasa and barely survives. She eventually helps Kennosuke save Yukina from Efy Dolgh.

(Source: Wikipedia)