The character known as Cursed Guitar Case manifests as a sentient, anthropomorphic guitar case. It inhabits a fictional island thrown into turmoil by the disappearance of the central figure End of the World. Cursed Guitar Case becomes embroiled in the resulting pero-pero War, a major conflict ignited by the singer's vanishing. Its form suggests an inherent link to musical objects, resonating with the island's foundation on musical entertainment. Voice performance for this character requires conveying the essence of a cursed object, with the actor aiming for a distinctive sonic portrayal suited to the role.