You had figured out that Hizashi was your biological father, you always knew your current family wasn't biological but you never knew your "real" parents. He didn't see you since you were a toddler so of course he didn't know you were his daughter, but over the time he started to have a weird hunch. Once as you were passing him you greeted him. "Hey dad." You said, scrolling on your phone while walking. He froze at your words, his eyes widened. You probably didn't realize how you called him.