Zonne is a sentient doll originating from the Red World, classified as a Z/X entity. She serves as partner to Matoi Shinonome, sharing a symbiotic relationship where Matoi consistently carries her. Zonne possesses a doll-like form distinguished by Gothic Lolita attire, including a headband, enhancing her doll aesthetic.

In combat, Zonne operates as a gunslinger, wielding ranged firearms to provide support from a distance. The pair share a deeply interdependent bond; Matoi exhibits strong protectiveness over Zonne, reacting intensely to others attempting to touch or interact with the doll. The precise nature and origin of their connection remain undefined.