Carmen Ibáñez, daughter of a Federation Fleet veteran, grew up in Buenos Aires. In high school, she excelled at mathematics, history, and moral philosophy but struggled with biology, displaying particular squeamishness during insect dissections. These academic strengths secured her entry into the Fleet Academy, where high test scores and training led to her specialization in starship piloting. Though initially romantically involved with Johnny Rico, she prioritized her military career, resulting in their separation. She served as a crewmember and pilot aboard the Corvette Transport Rodger Young during the Bug War, participating in critical operations including the Battle of Klendathu, where she piloted through a disastrous troop drop. She survived the Rodger Young's destruction during the invasion of Planet P, escaping the crash with Zander Barcalow. After Zander was killed by a brain bug, Rico's Roughnecks rescued her. Carmen subsequently attained the rank of Captain and received command of the starship Athena. Later, as captain of the starship John A. Warden, she confronted Minister Carl Jenkins when he commandeered her vessel for a classified mission to capture a live Arachnid Queen. Jenkins dismissed her objections, had her forcibly escorted off the ship, and transferred her to the Alesia. After the John A. Warden went missing, General Johnny Rico tasked the Alesia with locating it. Carmen insisted on joining the insertion team to retake her ship, stating her objective was ship recovery, not rescuing Jenkins. Boarding the compromised vessel, she worked to restore life support and navigation systems while coordinating with infantry teams. She discovered the Arachnid Queen had seized control of the ship's systems, directing it toward Earth on a collision course with Paris. Carmen collaborated with Major Henry "Hero" Varro and his squad to counter the threat. When sniper Tia "Trig" Durer partially disrupted the Queen's control, Carmen temporarily regained navigation to divert the ship toward the Alps, crash-landing it outside the city. Trapped aboard the wreck, she faced multiple bug attacks and received telepathic guidance from Jenkins to evade a Plasma Grenadier Bug. She was rescued by Rico's Marauder unit. After escaping via Jenkins' shuttle moments before the ship's destruction, she confronted Jenkins, slapping him and accusing him of destroying her ship, killing her crew, and endangering Earth. Jenkins apologized but asserted his research would ultimately save the galaxy. Carmen deduced he had telepathically guided her during the crisis, though he declined to confirm this.