Blue Mountain

Midori, better known by her pen name "Blue Mountain" Aoyama, is a writer who frequently visits Ama Usa An, Fleur de Lapin and Rabbit House. Her most famous work is The Barista Who Became a Rabbit, but she has also written a book based on Syaro Kirima, known as Caffeine Fighter. She wanders around town in search of ideas.

(Source: Is the Order a Rabbit? Wiki)