Facts about demon slayer

Facts about Kanao

Having trained under one of the Pillars of the Demon Slayer Corps, Kanao was the strongest of the group that survived the Final Selection, a group that included Tanjiro. ... Her winning streak continues until Tanjiro learns total concentration breathing and is then able to defeat her. May 19（Kanao's birthday was decided to be May 19, the day Kanae Kocho and Shinobu Kocho adopted her, since her actual birthday is unknown 16 years old selection 152cm→Around the time of ninth volume 156cm

She also loses the ability to see out of her right eye due to her using Flower Breathing's final form to take out the Upper Rank, with her eye gaining a defined pupil with a dark ring around it and becoming deprived of its gradient. Born into a poor family, Kanao was heavily abused by her parents, physically and through such things as starvation and isolation. Eventually, she's sold into slavery and, at some point, she breaks psychologically and becomes nearly catatonic