Marudashi, commonly referred to as Maru, is one of the two artificial attendants who reside in Yuko Ichihara's wish-granting shop. She is presented as a youthful, energetic girl with long, curly blue hair that she often wears in pigtails, and blue eyes. Her full name, Marudashi, roughly translates to "completely exposed" or "exposing oneself in public," a thematic pun that aligns with the series' playful use of the xxx prefix. Maru is always seen alongside Morodashi, known as Moro, and the two are often described as appearing like fraternal twins. They were created, likely by Yuko Ichihara or in conjunction with Clow Reed, as soulless beings tasked with serving the shop. Because they lack souls, they are physically unable to leave the shop's boundaries; if they attempted to do so, their bodies would disintegrate.

Maru's personality is cheerful, playful, and lively. She frequently acts with high energy and enthusiasm, often speaking in unison with Moro or finishing each other's sentences. She is devoted to Yuko and later to Kimihiro Watanuki, serving as a loyal helper and a source of lightheartedness within the shop. Despite her lack of a soul, she displays concern for those around her, sensing when Watanuki is troubled or unwell and reacting with care. Her motivations are simple and rooted in her function: she exists to assist Yuko, maintain the shop's magical environment, and carry out any tasks given to her. She finds joy in her duties and in teasing Watanuki, though she never acts with malice.

In the story, Maru's primary role is that of a supporting attendant. She and Moro welcome visitors, perform domestic chores, and provide a constant, stabilizing presence in the shop. They also serve a more significant supernatural function: their concentration is what keeps the shop hidden from ordinary sight and maintains its existence in the physical world. This responsibility requires them to enter long, deep sleeps periodically. When Yuko passes away, Maru and Moro briefly disappear, but Yuko uses the last of her power to bring them back, at which point their loyalty transfers to Watanuki, who becomes the new shopkeeper.

Maru's key relationships are with Yuko Ichihara and Kimihiro Watanuki. She is deeply attached to Yuko, serving her without question and with visible affection. After Yuko's departure, Maru transfers that same loyalty to Watanuki, continuing her duties under his ownership and helping to maintain the shop's routine. Her bond with Moro is inseparable; the two are almost never apart and function as a unit, though Maru is often portrayed as the slightly more assertive and quicker-tempered of the pair.

Over the course of the series, Maru's development is subtle. She does not undergo major personal growth in the traditional sense, as her nature as a soulless being limits her capacity for change. However, her role shifts from being solely Yuko's assistant to becoming a steady, reassuring fixture in Watanuki's long and solitary tenure as shopkeeper. Her continued presence provides continuity and a sense of normalcy in the shop's timeless atmosphere.

Maru's notable abilities are tied to her supernatural nature. She can sense spiritual phenomena and the emotional states of others. She and Moro together maintain the shop's concealment and existence in the world. She is also capable of performing various magical tasks under Yuko's direction and possesses the physical resilience of an artificial being. Beyond these, she has no combat abilities or independent magical power; her strength lies in her devoted service and her role as a keeper of the shop's boundaries.