Liavelt von Neuestein, often called Lia, is a recurring character in the Galaxy Fraulein Yuna series. She is the daughter of an old German count, which gives her an aristocratic upbringing. She first appears in the introductory sequence of the first game, where she helps a foreigner at an airport, but her primary role is that of the leader of the Thirteen Frauleins of Darkness, the elite servants of the Queen of Darkness. In this capacity, she initially serves as a rival and antagonist to Yuna Kagurazaka, the Savior of Light. She is described as the head of the Dark Queen's imperial guard and shows a persistent interest in Yuna, often meddling in her affairs.

Liavelt is a disciplined and capable warrior who wields a sword and commands considerable authority among her peers. She possesses a reserved and controlled demeanor, fitting her noble background. Despite her initial opposition, she is not purely malevolent. After being defeated by Yuna in the first game, she undergoes a significant transformation, becoming one of Yuna's closest friends and a powerful ally. This shift from enemy to ally highlights her capacity for growth and redemption.

Her motivations are shaped by her loyalty to the Dark Queen, but as she spends time with Yuna, she begins to question her earlier convictions. Her key relationships include her bond with Yuna, which evolves from rivalry to deep friendship, and her connection to the other Frauleins of Darkness, who she once commanded. Liavelt also has a secret identity as Polylina the Masked Maiden, a mysterious warrior, and an alter-ego known as Lia the Phoenix. These alternate forms emphasize her combat prowess and symbolic rebirth. She is also revealed to have the potential to become a Savior of Light herself and is classified as an esper, suggesting latent psychic abilities. Her notable skills include expert swordsmanship, leadership, and the ability to adapt her fighting style through her masked persona. Over the course of the series, Liavelt develops from a formidable antagonist into a trusted companion, demonstrating a journey of self-discovery and loyalty.