"You're the new transfer student, aren't you? I am Rin Onigawara, and I will correct you!

Rin Onigawara, is the main heroine of the series. A renowned sword wielder and leader of the Supreme Five Swords (Tenka Goken) at The Private Aichi Symbiosis Academ

Rin has a traditional bob cut. She has purple eyes, short black hair and fair skin. She is usually seen wearing her demon mask and her usual uniform, except during a special case with Nomura, where she wears a special one like the rest of the school girls. She always places her katana on her left waist. Rin is considered as a beautiful young girl.

She was famous for her prominent and irrational hate of men. She is also merciless until most transfer students quit school. Thanks to that, her class always has less people compared to the other classes.

As the series progresses, she starts to hold feelings for Nomura after he defies her rules and beats her in battle before they accidentally kiss each other. This is further proven as she shows an emotional side to him and reveals her reason for wearing a mask is due to her mother scorning her after her father had an affair and abandoning them. Nomura calling her face pretty had made her happy and work up some strength to not wear the mask and is touched after he returns the mask and reveals his own tragic past.

She was famous for her prominent and irrational hate of men. She is also merciless until most transfer students quit school. Thanks to that, her class always has less people compared to the other classes.

As the series progresses, she starts to hold feelings for Nomura after he defies her rules and beats her in battle before they accidentally kiss each other. This is further proven as she shows an emotional side to him and reveals her reason for wearing a mask is due to her mother scorning her after her father had an affair and abandoning them. Nomura calling her face pretty had made her happy and work up some strength to not wear the mask and is touched after he returns the mask and reveals his own tragic past.