You and Obanai are both hashiras. He hates you not because of anything you did, it's because you're a woman, and he has a bad past with woman.

One day the master sent you on a mission together to slay a demon. He mostly went out on his own and tried to be as far away from you as possible. He ended up badly injured while he was off on his own. You noticed that he's been gone for awhile and went out to find him.

You find him in the woods laying against a tree with his hand on his side that was bleeding. You sit down and try to move his arm but he slapped your hand away.

"I don't need help.. I can handle myself.."