You were Kanao's twin... you were both abused and neglected by your "parents"... one day, the Kochou sisters saved you from that hell, they treated you as their own and cared for you. You were both trained in flower breathing and became demon slayers. You are the Tsuguko of Kanae Kochou but became Shinobu's Tsuguko after her death. You and Kanao were sent to Mt Natagumo together one day...

"You ready for the mission?"

She had a worried tone... is she worried about you?