Karla Mitchum works as a scientist for the Principality of Zeon's military, specializing in prosthetics and biological interfaces. Her core mission involves developing advanced prosthetic limbs and refining the Reuse P Device (RPD) system for the amputee pilots of the Living Dead Division, aiming to improve their synchronization with mobile suits. She serves Zeon driven by a personal goal: securing the release of her imprisoned father, a historian branded a political dissident by the regime. Within the Living Dead Division, Karla forms pivotal relationships. She enters a romantic relationship with Ensign Hoover, the unit's initial mobile suit team commander. Hoover's death at the hands of Federation pilot Io Fleming shatters Karla, igniting a fierce desire for vengeance. She explicitly tasks pilot Daryl Lorenz with killing Io. Her connection with Daryl evolves significantly as he sustains further combat injuries against Io, necessitating additional amputations for enhanced Psycho Zaku compatibility. Shared trauma and dependence forge deeper bonds, culminating in romantic feelings. They share a kiss before Daryl's final sortie in the Thunderbolt Sector, where he later names Karla his reason for living. The Thunderbolt Sector inflicts severe psychological trauma on Karla. During the Federation assault on the Zeon flagship Dried Fish, she attempts to stop fellow scientists from detonating scuttling charges after Cornelius KaKa's pleas cause hesitation. As she moves to intervene, Federation forces vaporize the entire team with a beam saber. Witnessing this atrocity triggers a catatonic state. She remains unconscious until after the One Year War concludes. Upon waking, profound psychological damage manifests as severe regression; her mental state reverts to that of an adolescent. She fails to recognize Daryl as her partner, instead identifying him as her "papa." Daryl continues visiting and caring for her, demonstrating unwavering commitment. She remains under the care of a Zeon medical team aboard a submerged Dolos-class ship operated by Zeon remnants. Beneath her service lies deep-seated resentment. Despite her contributions, Karla harbors intense hatred towards Zeon and, later, the South Seas Alliance. She perceives both factions as exploiting her work and using her solely as a tool for their agendas, especially post-war. This bitterness fuels a willingness to take extreme actions, including firing a colony laser at a colony itself. Her skills extend beyond prosthetics into manipulation, leveraging relationships with Daryl and South Seas Alliance members to advance her own objectives. Her arc illustrates a shift from a scientist motivated by familial loyalty to a traumatized individual grappling with loss and exploitation, culminating in profound psychological breakdown.