『Mahiro Oyama』

The protagonist of Onii-chan wa Oshimai. He was turned into a girl thanks to his little sister by drugging him.

Age: Around 20

Birthday: March 6th

Blood Type: O

Height: 144 cm

Weight: 38 kg

Gender: born male transformed into female

School Grade: finished school for more than 2 years, entered Jr high school as a female

Interests: Video Games, sleeping late

Mahiro's male appearance is shown once in the manga which depicts Mahiro with shorter hair and the face looking very similar if not exact, along with one scene where they are shown with their back to the audience. The story begins with Mahiro already having the appearance of a typical cute teenage girl.

She is the same height as her sister, Mihari.

As with Mahiro's male appearance, not much is told in the manga about what Mahiro was like as a male. Most of the information is presented as references or as implications from comments that the two sisters make to one another. The most telling aspect of the personality is when Mihari calls them a 'A Trashy Hikikomori N.E.E.T.'

Mahiro seems to have always had an outlook on life that was like that of a rudderless sailboat. That is to say they never had much of a goal to work towards, and very much just accepted what came their way without much concern or reaction.