Loux Krystas is an immortal witch who has lived nearly three hundred years, bearing the title of the Dawn Witch. Her unexplained longevity and perpetual youth originate from a contract with a demon inhabiting her semi-sentient staff, Luden. This staff shifts forms and actively drains the magical power of anyone touching it, usually fatally. Consequently, Loux cannot wield significant magic independently and relies entirely on Luden for power.

Despite her childish demeanor, Loux possesses centuries of accumulated wisdom and knowledge. Her outward behavior often masks her deep understanding of magic and history. She serves as a professor at the Royal Academy of Magic, mentoring and escorting students like Saybil, Hort, and Kudo on field missions to gather intelligence on Remnants of Disaster, providing protection and tactical support during perilous encounters.

In combat, Loux exhibits formidable proficiency with Luden, confronting adversaries such as Holdem and Mercenary. Opponents avoid direct clashes when victory seems uncertain. Her dependence on the staff becomes a critical vulnerability when she surrenders it to Tyrant of the witch-hunting faction Dia Ignis to save her students, demonstrating her commitment to their safety despite personal cost.

Loux shares significant ties with other witches. She maintained a close bond with Sorena, the Mooncaller Witch, until Sorena’s wrongful execution by burning. Loux actively seeks to study the Grimoire of Zero and meet its creator, Zero, reflecting her scholarly dedication. Her actions directly disrupt conspiracies against witches, such as exposing Bishop Edmeanor’s plot to incite war using a Remnant of Disaster.

Her lineage proves pivotal, as Luden responds solely to her bloodline. This trait emerges when Saybil wields the staff unharmed, suggesting a familial connection. After neutralizing major threats, Loux achieves her objective of studying the Grimoire of Zero within the Forbidden Library.