The RX-105 Ξ Gundam, also referred to as the Xi Gundam, takes center stage in the Mobile Suit Gundam Hathaway movie. Acquired by the Anti-Earth Federation group Mafty for the pivotal attack on the Adelaide conference, this cutting-edge mobile suit was skillfully piloted by Mafty Navue Erin. Developed and constructed by the renowned Anaheim Electronics, both the Ξ Gundam and its counterpart, the RX-104FF Penelope, were classified as fifth-generation MS, boasting advanced features essential for their roles.

Distinguished by its built-in Minovsky Flight Unit and equipped with the latest Beam Barrier system, the Xi Gundam stood out as a truly autonomous fifth-generation MS. In contrast to the Penelope, which relied on optional units for similar functions, the Xi Gundam was a self-sufficient powerhouse. Its arsenal included standard equipment such as a Beam Rifle and Shield, along with the unique addition of Funnel Missiles, making it a heavily armed and formidable unit on the battlefield.

One of its distinctive external features was the large arms, which also doubled as containers for Triple Missiles. The Xi Gundam's iconic design and high degree of perfection were put to the test in intense battles against the Penelope and the Circe Unit, with Hathaway Noa skillfully commanding the cockpit. This mobile suit's remarkable capabilities and weaponry added a layer of complexity to the narrative, showcasing its pivotal role in the Hathaway movie.