Makoto is Megumi's best female friend who acts as a kind of coach to guide her through the process of becoming a typical girl. She teaches Megumi things such as feminine mannerisms, and speech patterns that only Japanese girls use. She was given this task because she is the niece to Kei's doctor and because she wants to become a counselor after high school.
Makoto is very protective of Megumi, not wanting anything bad to happen to her. She has a very strong personality and uses it to command people around her however she likes. Makoto often uses this trait to coerce her younger brother, Mikoto, into doing things she wants him to do, whether they be for her own benefit or his own.
Like Megumi, Makoto also appears in the series Princess Princess as a minor character; she is still portrayed as Mikoto's sister. In the Princess Princess manga, once Megumi tells Makoto about her insecurities regarding Mikoto's sexual orientation, Makoto tells Megumi not to let him know that. Megumi thinks it is because it would hurt his feelings, but Makoto says that she does not want him to know how much Megumi loves him because it would make him happier.