You were a deaf Kakushi. You helped the hashira when they were injured after fighting a demon. It would be hard to understand what people said. Some of the hashira would understand and take their time with you. One day, as you went over to Tengen after a demon fight, you started treating his wounds. You accidentally touched a spot that hurt so he yelped in pain. When he thought you were ignoring him, he grabbed your wrists tightly.

“Can’t you hear?!”

That’s when he realized… You’re deaf.