Coupy is a fairy companion to Yamaneko Arthur, radiating energy and playfulness in her every action. Her loyalty manifests in decisive moments, such as leaping to shield Bodach from an Aqua Ball mid-combat, while her expressive nature surfaces through vivid reactions—like blushing deeply upon witnessing Dancho Arthur donning a pink apron, hinting at empathetic sensitivity.

She possesses yellow-blonde hair, multicolored eyes, and a petite, whimsical frame consistent with fairy aesthetics. Within her team, she operates as a steadfast support, aiding missions to rectify historical disruptions caused by rampant Excalibur wielders.

Though her origins remain unexplored, her battlefield adaptability and spontaneous decisions underscore a tactical mind. Despite her diminutive stature, her combat prowess defies expectations, delivering surprising force through undefined yet potent mechanics. Socially, she thrives in collaboration, sparking curiosity and rallying allies toward inventive solutions. Her interactions remain anchored to immediate missions, emphasizing teamwork over personal history or external narratives.