For centuries, Altea had been at war with planet Heracles, with each world's ruling dynasty founded by royal brothers who were bitter rivals. Amue was born the middle of three children of King Heracles, with her older brother Crown Prince Samson, a great warrior, set to inherit the throne, and her younger brother Prince Alor devoted to his older siblings, whom he admired and loved. As Altea and Heracles came into a near orbit that only happens every few decades, King Heracles made the fateful decision to ally his world with Emperor Daibazaal of Galra, in order to crush Altea once and for all. This was a doubly foolish decision, as Galra knew well of his ambition to then turn on them with their own weapons.
The boasting braggard nature of Galra's Prince Imperial Sincline placed him in arena combat with Amue's brother Samson, who bested Sincline, arguably because he was distracted by Amue, who is very nearly a twin for Altea's Princess Fala. At first, both Amue and Alor were enthralled by Sincline's facade of being a noble warrior. Amue accepted a feast in her honor held by Sincline, and apparently stayed in his company for several months, in that time seeing his true cruel face, though her younger brother refused to believe this. Also during that interim, her brother Samson was transformed by Sorceress Honerva into a MechaBlack DeathBeastMan at his own request, to fight and best Go Lion in personal combat. A process the Heracleans thought controllable and reversible had in fact left Samson irrevocably a monster. While treachery continued to build on both sides, the Heracleans issued a challenge to the Alteans that was received by Minister Raible.
The Go Lion team decided to infiltrate Heracles and make peace if possible. The two princesses met and seemed predisposed to peace (the shock of their resemblance to one another after generations took everyone by surprise), but a mishap with the resistant Prince Alor sounded the alarm and summoned the Galrans, who already knew of their infliltrators. The team managed to get back to the five lions, but Go Lion was soon challenged by the transformed Samson, who briefly had them on the ropes until the team rallied. Disgusted by Samson's performance, Sincline ordered his ships to fire on both combatants. Samson was killed in front of his family, followed swiftly by King Heracles himself when he took up a battery position to fire on Sincline. Galran soldiers seized Amue, and despite the best efforts of her younger brother and Go Lion, Sincline escaped with her as a prisoner.
A few months later, Amue and some of her ladies in waiting captured with her attempted a daring escape using a Galran slave ship, just as the Go Lion team had originally. This was intercepted and the ship forced down on an ice planet. When Alor tried to rescue his sister, he too was seized by Sincline, who demanded Fala surrender herself in exchange for them. A rescue attempt by team leader Kogane kept Fala safe and rescued Alor, but not Amue. Once more, despite the team's best and cleverest efforts, Sincline again escaped with Amue.
The many months of being Sincline's prisoner were hard on Amue, especially considering she was not truly who he wanted, being a stand-in for his obsession with Fala (Sincline would learn the basis for this later in life). It is strongly implied that Sincline raped her during this period. She was often displayed like a prize catch, chained up and suspended in the Galran court. Finally, during an effort by Daibazaal, Honerva and Sincline to trap Go Lion in a gravimetric prison caused by a dwarf star, she twice aided the super-robot, the first time being a set-up by her captors to further entrap Go Lion, but the second actually helping. As revenge, Sincline had her put before a firing squad, but she fell into a crevasse and was rescued by a seeming wildman who turned out to be Shirogane Ryou, brother of Shirogane Takashi, the original pilot of Blue Lion before Princess Fala. Despite Ryou's efforts to push her back, Amue rapidly began to have feelings for her rescuer, who helped her to stand strong and join with other Heraclean prisoners, who gave their lives to see her free. Together with Ryou, she escaped Galra entirely and was reunited with her brother and their friends.
Despite Alor's protests, Amue joined with Ryou on recon and sabotage missions on Galra and achieved some impressive victories, and it also became obvious that Ryou loved her as well. When the final battle came, the aid of their group proved vital to helping Go Lion beat back the defenses on Demon Castle on Galra. Determined to avenge his fallen brother, Shirogane Ryou attempted to take out Sincline personally, only to be taken captive by a desperate Sincline, who ordered Go Lion to be put out for destruction in exchange for Ryou's life. As Amue watched, Ryou stabbed Sincline and then knocked him off the high precipice they were on. Amue mourned as Ryou was buried next to his brother. Her subsequent fate is unknown, nor is it known if she ever recovered from this heartbreak in the midst of final victory over their enemies.
Amue's American counterpart, Romelle, had a happier fate on several fronts, mostly due to the edits made for Voltron. The happiest of these changes was the survival of her love, Sven, whom she grew closer to in the series' specially-produced second season.