Cosmos is a character from the anime Fairy Tail, serving as a member of the Garou Knights, also known as the Hungry Wolf Knights. This group functions as an independent executioner unit that operates from the shadows to support the Kingdom of Fiore. She appears during the Grand Magic Games arc when the rescue team from Fairy Tail falls into the Abyss Palace, a prison where the kingdom sends criminals to be eliminated.

In terms of appearance, Cosmos has long, somewhat messy pink or violet hair and dark eyes. She typically wears a large puffy cap with a brim that covers her eyes, featuring a decorative pattern on the front. A rose is often tucked into her hair on the left side. Her attire consists of a long coat with petal-like edges and ruffled details, complemented by a ribbon belt, a short skirt, arm sleeves, and long boots. A flower bracelet adorns her right wrist.

Cosmos possesses a calm and composed demeanor but has a notably cruel and ruthless side as an executioner. She carries out orders to eliminate those labeled as criminals without hesitation, fully convinced of her duty to the kingdom. Her speech often includes the word beautiful, reflecting a poetic or romantic nature that contrasts sharply with her lethal actions. She shows a peculiar fondness for the Dragon Slayer Wendy Marvell, blushing and touching Wendy's face while attempting to execute her, and expressing admiration for her screams. However, this twisted affection turns to rage when Wendy resists her magic, leading Cosmos to declare that she has been deceived and is no longer loved. Additionally, she dislikes flirtatious men, particularly the Celestial Spirit Loke.

Cosmos wields Plant Magic, specifically focusing on flowers and spores, which she uses to attack and kill her opponents. Her magic is designed for lethality, distinguishing her from other plant magic users in the series. She often makes her entrance by emerging from a giant flower. Her known techniques include summoning a large man-eating plant that closes its petals around a target, and Grow Flow, which creates a massive flower that generates a powerful suction force to draw enemies into its center. She can also produce Spore Bomb: Rinka Renka, explosive spores that bombard the opponent, and Makura Kamura, a deadly sleeping spore that induces an eternal slumber from which the victim never wakes. In the anime adaptation, she additionally demonstrates the ability to grow magical fruit from a tree, which she fires like projectiles, and she is noted to have a particular fondness for sour flavors.

In the story, Cosmos first battles Wendy Marvell. After Wendy uses her support magic to grant herself status ailment resistance, she withstands Cosmos sleeping spores and defeats her with the Sky Dragon Slayer technique Shattering Light: Sky Drill. Later, Cosmos reappears alongside the other Garou Knights to assist royal guards in battle. She faces Wendy again but is soon confronted by Loke. Cosmos shows irritation at Loke flirtatious advances. Ultimately, she is defeated and consumed by shadow magic. Throughout her appearances, she remains a loyal and dangerous enforcer for the kingdom, though she undergoes no significant personal development, serving primarily as an antagonist during a single story arc. Her partnership with fellow knight Kamika demonstrates effective team coordination in combat.