Tokuo has long black hair that reaches past her waist, and dark eyes. She bears some resemblance to her brother, Hinata. She wears the school's standard winter uniform, except with the jacket slung over her shoulders to cover up the fact that she is pregnant.
Hourai was born into a wealthy, noble family. Much of her past is unknown though her colleague whom had also graduated with Hourai during their time in Naraka High School, accuses Touko Hourai of murdering her past adopted brothers when they all had mysteriously died in different circumstances. This is only a speculation, though Hourai has never denied the fact.