Layla Ashley is the protagonist of the anime Avenger, set on a post-apocalyptic, colonized Mars. She is a Barbaroi, a term for gladiators who live outside the domed city-states and compete in representative battles. Layla is about eighteen years old, with long brown hair and blue eyes, and she typically wears a cape and belt. Her past is marked by tragedy: as a young girl, she traveled with her family and other pilgrims from Earth's moon to Mars aboard a colony ship. The ship was destroyed on the orders of Volk, the ruler of Mars, who sought to prevent the human cargo from further straining the planet's scarce resources. Layla was the sole survivor, placed into an escape pod before the vessel was obliterated. This event fuels her deepest motivation: revenge against Volk. She carries a deep, simmering hatred for him, which she rarely expresses overtly but drives much of her actions.

Layla's personality is quiet, brooding, and emotionally reserved. She rarely shows any emotion on her face, and her demeanor is cold and detached, often giving the impression that she lacks a will to live. She harbors a general disdain for Dolls, the childlike robots that have replaced human children on Mars due to a decade-long infertility crisis. However, she makes an exception for Nei, an unregistered Doll who travels with her. Layla cares for Nei intensely, showing a warmth and protectiveness that she extends to no one else. Their bond is almost maternal, and Nei is the only being for whom Layla consistently displays emotion. How and where she met Nei remains unknown, but Nei was given to Layla as a prize for winning a fight, having been found abandoned in a trash pile.

In the story, Layla serves as the representative fighter for Serena City on Mars. She participates in official gladiatorial tournaments and nearly always wins decisively, but she tends to avoid cities to evade unnecessary official challenges. Her primary quest is to confront and defeat Volk, the authoritarian ruler of Mars who orchestrated the destruction of her colony ship. She travels across the harsh Martian wilderness accompanied by Nei and Speedy, a cheerful doll breeder from Serena City. The trio faces constant attacks from Volk's forces, who view Layla and Nei as threats to the established order. Through these encounters, Layla's tragic past and the mysterious nature of Nei are gradually revealed. As the series progresses, Layla's emotional walls begin to crack; she learns more about her own origins and Nei's true nature, leading to a slight but meaningful development in her character. She remains primarily focused on her goal of vengeance, but her bond with Nei becomes a source of strength and a reason to keep moving forward rather than simply seeking death in battle.

Layla's notable ability is her exceptional combat skill. She is a top-notch gladiator, renowned across Mars as a powerful Barbaroi fighter who wins her matches with apparent ease. Her fighting style is natural and instinctive, as if combat is the most ordinary thing in the world. She wields a weapon—often a staff or blade—and demonstrates quick reflexes, strength, and tactical awareness. Beyond her physical prowess, she possesses resilience and endurance to survive in the unforgiving Martian environment. Her determination and willingness to protect Nei also serve as intangible strengths that push her to keep fighting even against overwhelming odds.