Artesia Som Deikun, later named Sayla Mass, emerged from a politically influential lineage as philosopher Zeon Zum Deikun's daughter and Casval Rem Deikun's younger sister—the future Char Aznable. After her father's assassination, she and Casval fled to Earth under Jimba Ral's protection, evading Zabi family persecution. Adopted by wealthy Don Teabolo Mass, she took the name Sayla Mass while her brother left for Side 3. She remained with the Mass family in Spain, later relocating to Texas Colony. Following Jimba Ral's death in an assassination and Teabolo Mass's passing, she pursued medical studies on Side 7, dedicating herself to volunteer healthcare over political entanglements. The One Year War erupted when Zeon attacked Side 7, forcing her evacuation aboard the SCV-70 White Base. During a reconnaissance mission, she recognized pilot Char Aznable as her brother Casval, compelling her to join the crew as communications officer and nurse. Despite her medical focus, she displayed unexpected piloting skill, briefly commanding the RX-78-2 Gundam to gather intelligence on Char. This resulted in disciplinary confinement but secured her role as backup Gundam pilot, later advancing to G-Fighter and Core Booster units. Her combat proficiency grew through latent Newtype abilities granting limited spatial awareness and empathy, though less developed than Char's or Amuro Ray's. Aboard White Base, she maintained professional rapport with Captain Bright Noa, who addressed her formally despite knowing her identity. She forged a close bond with Amuro Ray, evolving into romance in novelizations where they became wartime lovers. Her encounter with Ramba Ral—Jimba Ral's son—during a boarding operation led him to identify her as Artesia. His suicide and deaths like Ryu Jose and Matilda Ajan deepened her aversion to unnecessary violence. Repeated wartime confrontations with Char exposed their ideological rift. At Jaburo and Texas Colony, he urged her to abandon the Federation, offering gold for a new life. She refused, donating the gold to White Base as a loyalty symbol. Their final clash occurred at A Baoa Qu, where she intervened in Char and Amuro's duel, pleading for peace. Char redirected his efforts against the Zabis, ordering her to escape with Amuro. Though separated during evacuation, both survived. In "Mobile Suit Gundam: The Origin," her A Baoa Qu role expanded: piloting a customized GM in combat before Zeon capture. Revealing her Artesia identity inspired Zeon soldiers to revolt against the Zabis. Their leader, Captain Matogurosu, sacrificed himself to save her from explosives, enabling her to reach Char and Amuro's duel. Post-war, she established a war orphan foundation aiding Jill and Milly Ratokie, earning Kai Shiden's gratitude. During the Gryps Conflict, she observed Char's Dakar speech. In the First Neo Zeon War, she rescued Leina Ashta and informed Bright Noa that Char's ambitions threatened peace, suggesting his death might be necessary. By U.C. 0095, as an investor, she discussed Char and Amuro's trauma from Lalah Sune's death in a Kikka Kobayashi interview. She consistently believed Char survived as an Earth Sphere destabilizing force. Her character rejected vengeance despite tragedy, prioritizing healing and protection. Standing 165 cm tall, her calm demeanor reflected medical training and aristocratic upbringing. Though combat-capable, she consistently valued empathy and life preservation over military objectives.