Kotori Makino, one of Kanna Aoyagi's closest friends at Takashima Minami High School, possesses black hair styled in twintails, striking red eyes, and stands 1.45 meters tall weighing 38 kilograms. She speaks in a characteristically soft-spoken tone.

Kotori is observant, quickly noticing subtle shifts in Kanna's behavior which spark her curiosity. She actively investigates these changes, questioning Kanna directly and collaborating with their mutual friend Hazuki Noge in activities like spying to uncover the secret. Although she doesn't initially discover Kanna's exact role in eroge voice acting at Blue March, Kotori correctly deduces it involves sexual content, particularly after observing Kanna's interactions with classmate Motoki Kaizu.

Leveraging her youthful, loli-like appearance as a casting factor, Kotori eventually joins Blue March as a voice actress. She is explicitly identified as a virgin and maintains this status. An avid gamer, this hobby reflects her personal interests outside school and work. Her narrative role centers on her persistent curiosity about Kanna's secret and her subsequent entry into the same industry.