Michiru attends the same school as Yumiko, although in a different section, and is one of her best friends since childhood. A quiet and overly serious girl, Michiru can be quite dry with her comments, one of the reason she is found to be not too approachable. Her way of thinking often clashes with the easy-going attitude of Sayuki, and they often end up arguing (even if they secretly respect each other). She is very attached to Yumiko, and she can become extremely unpredictable if she feels that her friend is threatened in any way.
For some reason, Michiru is extremely skilled at handling UFO catchers, and it is not unusual for her to win the best prizes when she plays.