Minki

Minki is the youngest, but just as destructive (and annoying) female sibling of the oni family. Although she possesses similar power and abilities to her older brothers Baki and Zekki, the source of her (and possibly all the oni) power comes from a pair of panties that she wears. (according to legend, most of an oni's spiritual power comes from their underwear or loincloth) When she accidentally loses her panties in the human world, she is forced to cross over to get them back, even if it means making everyone at Doumori Elementary nude in the process. Although she sort of gets them back (they were being worn by the perverted Ishikawa-sensei), Nūbē seizes them and, in a strange move, makes the Oni-girl join his class. His belief was that outside her panty-powers, Minki was a quiet, nice girl who needed to learn a few things. Although she seemed rather strange at first, Minki showed a protective, kinder side than she initially portrayed, even protecting her classmates just as Nūbē does. But at the moment she got her panties back, Minki regained her full, demonic power and attitude, fighting against her teacher and particularly showing hatred for the males of the class. But at the climax of her rampage, just as she prepared to destroy her teacher and school, her panties fell off her body once again, making her drop her attack and nearly destroying her in the process. Nūbē saves her, however, believing her to be different from the other Oni and choosing to give her a second chance in the human world. After nearly destroying the school and Nūbē, Minki becomes both a valuable student and a key ally in his battle to protect his students and fight against intruding enemies and yōkai. Although she does not contain all of her Oni power as she did with her panties, she does have enough to occasionally play naughty tricks on her friends and classmates. (she slowly does seem to accept them as friends, but has a hard time doing so due to her own circumstances) She is also able to assist her teacher in a valuable way: as he faces a couple enemies that force the Oni no Te away from him, Minki is able to fuse with Nūbē to allow for her Oni power to be used by him. A key difference between her and Baki's arrangement, though, is that the teacher is able to use a fuller extent of Minki's power due to theirs being a conscious partnership. Outside of battle, Minki not only sees Nūbē as her teacher, but her "big brother" as well, as her 'real' big brother is sealed in his hand. This leads to some rather awkward situations between the meaning of being a human sibling to being an Oni sibling. Minki is the only member of the Oni siblings that does not have a full demonic form. Although she can exhibit oni appearance such as her scantly clad appearance and demonic hands and feet, this form takes more of a human appearance than either Zekki or Baki. (possibly showing an influence from the American comic series Witchblade) Just as peculiarly, two horn-like protrusions that allow for the formation of her long pigtails remain visible both in "human" and "Oni" forms. (Source: Wikipedia)