Willa is the queen and leader of the Warrior Maidens, a tribe of strong, Amazonian-like female warriors who reside in the Treetop Kingdom on Third Earth, protecting its forests from threats. She first appeared in the fifth episode of the original ThunderCats series, titled "Trouble with Time," aired in 1985, where she and her sister Nayda assist the ThunderCats in rescuing Tygra from the accelerating effects of the Cave of Time. Voiced by Lynne Lipton, Willa is portrayed as a confident and authoritative figure, with Nayda serving as her younger sister and second-in-command, skilled in scouting and archery.
Characterized by her initial suspicion toward outsiders, including both the ThunderCats and the Mutants upon their arrival on Third Earth, Willa embodies territorial protectiveness and martial prowess. She is an expert archer, wielding a bow and arrows with precision, and leads a diverse group of barefoot warriors drawn from various ethnic backgrounds. Her tough demeanor and leadership qualities make her a formidable ally, though her early distrust reflects the Warrior Maidens' isolationist tendencies.
Through repeated interactions, Willa develops a strong alliance with the ThunderCats, transitioning from caution to loyalty as they prove their worth against common enemies. Appearing in approximately thirteen episodes across the series, she provides crucial guidance on Third Earth's terrain and participates in key battles against villains such as the Mutants and Lunataks. Ultimately, after major threats are neutralized, Willa and Nayda join the League of Third Earth, solidifying their role as enduring supporters of the ThunderCats' cause.