Mudie Holcroft, a Natural human and Earth Alliance Phantom Pain special forces Ensign, was forged through rigorous military training from childhood after becoming an orphan in a Blue Cosmos care facility. This environment instilled deep anti-Coordinator beliefs, including the repeated mantra "the only good Coordinator is a dead Coordinator," which she later quoted during operations.

Specializing in close-quarters combat, Mudie piloted the customized close-combat GAT-X1022 Blu Duel Gundam. She operated in a three-pilot squadron alongside teammates Sven Cal Bayang and Shams Couza. Without physical augmentation or Extended mental conditioning, her combat skills were nevertheless considered exceptional for an unaugmented human.

Mudie displayed an aggressive, eccentric personality, often wearing flamboyant makeup and a modified, revealing military uniform. While generally dismissive of outsiders, she showed loyalty and camaraderie to her immediate teammates. Her profound hatred of Coordinators fueled ruthless combat actions against perceived enemies.

During the Second Alliance-PLANT War, Mudie participated in escort operations for advanced weapons like the GFAS-X1 Destroy Gundam prototype. Her team engaged Martian pilot Ergnes Brahe in his Δ Astray. Later, during Phantom Pain's assault on the DSSD space station, Kerberos BuCUE Hound units disabled her Blu Duel Gundam, severing its limbs and leaving her defenseless. Three Kerberos BuCUE Hounds simultaneously attacked the cockpit, killing her. This marked the first Cosmic Era Gundam pilot death by mass-production units.

Mudie's death deeply impacted teammate Shams Couza, triggering extreme personality changes and heightened aggression during the DSSD assault. The nature of their relationship prompted observer speculation about possible romantic connections.