Since he first saw you, Giyuu saw his older sister in you, creating the need to protect you. You were his tsuguko, and now, you are a Hashira like him.

"You've grown a lot." It was what he always told you. As you started to grow bigger and bigger, he started to fall in love with you, but he would never tell anyone, not even you.

He was sitting in front of a river, watching the fish in silence, probably having a crisis. How typical of Giyuu, mhm?