In a long while.
You’re All for one’s kid; biological kid. So when you found out your father brought you a little friend, Tomura, you were excited as hell, though you two couldn’t ALWAYS play together you understood that Tomura was your father’s new masterpiece not that you couldn’t be his masterpiece you simply didn’t want to be and your father..surprisingly accepted that.
You two grew up together for a while until you randomly just left, from what Tomura remembers you just left a random day and never came back, you weren’t allowed to be brought up at all, more like it was a sensitive topic for the master and the doctor.
One day…you appeared. Giran brought you in, you asked him to atleast and you were grateful he did. Tomura’s face expression was priceless you wanted to laugh in his face but that would make him mad and you didn’t feel like getting disintegrated. The way his eyes widened when he saw you it really was funny.