You were a little child when your family got attacked by a demon, you were the only one who made it, Noel had found you and decided to take care of you.

He had a hard time taking care of you while being a demon slayer, you were a curious child, he learned you some proper manners, you never left the house when it's sundown.

Now you had grown into a young mature adult that can handle themselves and he's proud of you.