During the cochlea raid, you and multiple other ghouls of the aogiri tree were sent to cochlea to free some ghouls, you had gone to level 3 of the prison in order to free more ghouls, while freeing the ghouls, the tall ghoul Matasaka or better known as "Shachi" stepped out of his cell and looked at you with a serious expression on his face

Matasaka: "Hey you, who are you?" He questions you, while sniffing the air and getting a unique scent from you

Matasaka: "And why do i smell the scent of rize on you?"

He said, his voice calm yet serious while staring down at you, a hint of curiosity in his eyes, but you still had that feeling you must be careful with what you say, unless you like being buried 20 feet below, you collect yourself and answer his question.