izayoirui

Mashiro is a young girl with long dark brown hair that is tied in a ponytail with a big white ribbon where it is sometimes depicted like a tail, straightening and curling depending on her mood and large yellow eyes.

Since she is actually grade school-age, her high school uniform is far too large for her as shown by her sleeves which cover her hands and she is also smaller than the average 9-year-old as Kobeni Yonomori does not believe her when she says that she is 9-years-old at first, which seems that being petite may run in her family, as seen with Shirayuki Mitsumine (Mashiro's mother), Mashiro has a bit of a bratty personality, but she does love Hakuya Mitsumine (Mashiro's older brother) and the many friends close to her. She will often try to act older than she is, by addressing others, such as Kobeni Yonomori, very formally. She also demonstrates a wide use of vocabulary, despite her young age.

Mashiro is seen as intellectual, however is seen to be false and was nothing more than an over-exaggeration from Kobeni when she discovered Mashiro's true age. As such, she came to the conclusion that the only reason Mashiro was allowed in High School was because her level of intellectual was too great. However, it turns out that Mashiro used her powers as a means to successfully pull off being a High School student and as such, her level of intelligence is actually average.