Miyako Arima appears within the comedic and exaggerated Carnival Phantasm series, portraying characters from the Type-Moon franchise. She is a cousin and step-sister to Shiki Tohno, belonging to the Arima family branch of the Tohno lineage, which possesses significantly weaker demon blood.

Following a traffic accident, Shiki Tohno resided with the Arima family, during which time Miyako developed deep admiration for him. Historically, her shyness and nervousness around Shiki prevented effective communication, often causing her to appear stern or angry despite her affectionate feelings. This dynamic continued until his return to the Tohno household, an event that distressed Miyako due to the reduced contact between them.

Physically, Miyako is small in stature, standing 131 cm tall and weighing 35 kg, with dark brown hair and green eyes. Her visual design incorporates a Chinese-inspired theme, typically featuring traditional-style attire. One victory pose in other media reveals casual clothing like shorts and a T-shirt printed with "大トロ" (Ootoro) underneath.

Miyako practices a self-taught form of Bajiquan martial arts, initially developed through observation in her family’s unused dojo. While her skills were rudimentary under ordinary circumstances, certain extraordinary events temporarily amplified her combat effectiveness. Her personality blends a desire to appear strong with underlying shyness, particularly evident around Shiki. She respects a mentor figure known as "Master Panda".

Within the Carnival Phantasm context specifically, Miyako is portrayed as energetic and childlike when focused on objectives. Her limited dialogue includes expressions of excitement about spending time with "Onii-chan" (Shiki) at the beach and nervousness about interacting with foreigners. This portrayal simplifies her broader character traits—such as her devotion to Shiki and social awkwardness—into comedic scenarios consistent with the series' parody style.