Miiko hardly expresses her feelings through facial expression, but surprisingly, she has a rough temper when fighting. Once information is received by her, it will be hard to make any changes to it afterwards. She likes sweet things, sake, and collecting antiques. Owns a Fiat 500, which is often borrowed by I. Can never stop getting into trouble with the guests at a new work place, but still finds a job teaching at a Kendo school momentarily.
Miiko is really concerned about "I"'s personality. "I" confessed to Miiko, but she reserved it saying she'll consider about it if "I" becomes a better man. Once had four relationships going at the same time, and three were girls, because she can't resist wanting to help the weak do everything for them.
Miiko loves drinking but hates smoking, opposite to her friend Neon who loves smoking but can't handle alcohol.
Miiko keeps her dark green hair in a ponytail and usually wears a jinbei with kanji representing her emotions at the moment over casual clothing at home.
Miiko is a twenty-two year old freeter, and a master of Kendo and Kenjutsu. Kicked out of her previous apartment, she was taken in by Nanami Nanananami after she found her wandering in the streets.
- Miiko's surname, Asano, is written with the characters for "superficial" and "civilian life" (浅, Asa = Shallow, Superficial; 野, No = Civilian Life).
- When Mikoko Aoii showed animosity towards Miiko, I thought it was because their names were similar, as Miiko's first name is similar in pronounciation to the word Miko, meaning "shrine maiden", while Mikoko's first name literally means "shrine maiden's daughter" (巫女, Miko = Shrine Maiden; 子, Ko = Daughter).