Esther is a character introduced in the second season of the anime. She presents herself as a masked knight who joins the hero's party as a mercenary. Her outward appearance is that of a woman with long black hair that reaches past her hips, and she is typically seen wearing a dress and a mask that conceals much of her face.

Her background is more complex than it initially appears. While she uses the name Esther, her true identity is Theodora. Prior to her appearance in the party, she had a notable achievement in the war against the Demon King's forces, having personally defeated one of the Demon King Army's Four Generals.

Esther is driven by a clear purpose. She becomes aware of a plot devised by Cardinal Lub, which involves sending the character Van to the town of Zoltan. Her primary motivation is to intervene and stop this plan from coming to fruition. This goal defines her role in the story, as her actions are centered on investigating and thwarting the cardinal's scheme.

Information regarding her personality, her specific relationships with other characters beyond her role as a mercenary, her development over the course of the series, and a detailed breakdown of her notable abilities is not available in the provided search results.