Emerelda Zubin operates as a member of the Mafty terrorist organization, serving directly under leader Hathaway Noa. Her duties encompass both logistical support and combat operations, exemplified by her dispatch to Davao to extract Hathaway following a hijacking by Mafty imposters. Within the group, she adopts an "older sister" persona, offering emotional support and camaraderie to fellow members. Emerelda initially aspired to be a professional mobile suit pilot but was unable to achieve this goal due to insufficient skill, a setback that ultimately led to her recruitment by Mafty where she serves in non-regular pilot roles.

Her film portrayal features a significant redesign from earlier depictions. Originally presented as a blonde-haired Caucasian in ancillary media, she was reimagined with Aboriginal Australian heritage, sporting red hair, brown skin, and attire incorporating Aboriginal patterns; this redesign process took approximately three years. Her film appearance frequently includes tying her shirt at the chest, exposing her midriff.

Operationally, Emerelda engages in critical missions, including a diversionary assault on Davao's Tasadai Hotel to aid Hathaway's escape from Federation forces. During this mission, she provides ground support, locates Hathaway amidst the chaos, delivers a coded note ("nejin"), and retreats. She later inherits Hathaway's former mobile suit, the Messer Commander Type, adopting the call sign "Messer 01". Her story concludes during Mafty's raid on the Earth Federation assembly in Adelaide, assigned to Me-02R Messer unit 1; she is shot down and killed in this engagement by Federation pilot Lane Aim.

Throughout her Mafty involvement, Emerelda demonstrates decisive action under high pressure, at times exhibiting greater resolve than male counterparts in combat. Her actions align with Mafty's objectives of challenging Earth Federation corruption and opposing policies like civilian deportation via "Man Hunter" units.