After her owner gives up on mending her stuffed rabbit, Mi-chan (to which the Character is named after), Yuka's egg is tainted with an X.
Later, when Rikka and Dia find her X-egg form, Dia notes that "it has a strong feeling of sadness coming from it" and it's power is to deprive people of willpower.
Then, Mi is reunited with Yuka and she explains that she is her 'would be self' and that she likes to do her best 'nice and slow'. Yuka then notes that she's heard Mi's voice before, telling her to stay calm and fix her stuffed rabbit slowly. After they exchange a few more words, Mi says "Let's take out time and slowly, gradually, eventually, turn into a girl who can do anything!" and then says goodbye to Yuka, returning to an egg once more.
Mi has cream-blond hair put in two ponytails with a curl on each end and bangs with a similar curl. She wears a pink-purple jumpsuit over her body with two white buttons sewn on the jumpsuit. On her hair is a similar white button hair pin.
Mi is a gentle, maternal girl, doing things at her own pace and reassuring others who have given up on the things they wanted to do.