Blue Mountain Aoyama, novelist pen name of Midori Aoyama, frequents cafés like Rabbit House, Ama Usa An, and Fleur de Lapin to write and mentor younger female characters. She presents an elegant image with medium-length sandy-blonde curls, lilac eyes, and a typical outfit of a white shirt, dark blue dress, and pale blue scarf, standing approximately 163 cm tall. Outwardly refined, speaking slowly and seeming absent-minded, she harbors a hidden perverse streak, notably attempting to look up girls' skirts. Her deep connection to Rabbit House began in school when its original owner, Chino Kafū's grandfather, encouraged her writing, reviewed her early stories, and gifted her a treasured fountain pen she considers irreplaceable. Losing this pen once made her contemplate abandoning writing. She reveres him as "Master," visiting Rabbit House partly hoping for a reunion. Her acclaimed novel *The Barista Who Became a Rabbit* is a favorite of Chino's; another work, *Caffeine Fighter*, drew inspiration from Syaro Kirima. She often wanders, seeking story ideas from observing town interactions. Her writing success includes a film adaptation. Her consistent role as an observer and mentor extends into franchise merchandise like character cards and solo music releases. Interactions, such as with Cocoa Hoto who interrupted her frantic pen search, showcase her approachable yet distracted nature.