Mika is very caring and considerate, but she has her limits. She and Yuki are fairly close as brothers and sisters, and she knows him well enough. Yuki used to call her "Mikarin," and Mika knows all kinds of useless information about him^^like how he needed lights in order to sleep until middle school. She's seen all kinds of women hang around Yuki and fall for him, but she doesn't understand him deep enough. She didn't think he would be able to take anyone in for a serious relationship, but Shuichi proved that wrong.^_^

Mika did not approve of Shuichi's relationship with Yuki at first, Yuki usually doesn't not listen to her and thinks she's only there to think of a way to get him to go back home. She tells him that he doesn't know enough about Yuki in hopes of having Shuichi stay away from him. You could say she's very protective of him, maybe even overprotective. The cause of this may be that she's seen Yuki hurt and suffer a great deal, and doesn't want him to go through it again. Later, Mika sees that Shuichi really likes Yuki, and she steps off. However, she tells Yuki to stay away from Shuichi when his memory started to come back. She fears that Yuki will not maintain his health with Shuichi around to bring back his memories and revive his suffering. But in the end, everything works out, Yuki's finally healing, and Mika has no more worries.^-^