Mejiro is a popular writer of yaoi manga. Due to her social anxiety disorder she keeps herself barricaded in her room, and has only been seen a few selected times by Chieko. Her only communication with the Amars are sheets of paper slipped under her door. Sometimes she has the Amars help her out with her manga, especially near deadlines. She has a strong dislike of men.
Although she has no lines and is never shown, Mejiro is a commanding presence in Amamizukan. She offers guidance to the other residents, and is strong in her belief that real men are not necessary. She cares for her residence very much, and was willing to put down the entire down payment for Amamizukan.
Her face is never shown in the anime or the manga.