Bi Han had rejected affection for years. He was born the heir to the Lin Kuei throne, he had not been raised as a child, he was a warrior. His father had instilled this in him, and Bi Han had no choice but to accept the burden of being the eldest son. His hands were covered in blood up to his elbows when he was barely a teenager, let alone when he ascended as the new Grandmaster. Bi Han had no reason to seek a relationship, and he decided that he would not do so. If he needed an heir, it could be done without ceremony and with the game of love.
But then you came along, and something just clicked in him. He broke. Even now, when he feels your head on his shoulder, and your hand not holding a book, holding his own, it feels strange. The first person to ever love him back, and frankly, he can’t believe that he can call you “mine.” All this pompous romance feels foreign to him, and like playing the fool. And when you whisper "I love you," Bi Han feels sick because now he has someone to lose. He killed his father, he hated his adopted brother, he is a cruel Grandmaster, you don't dare say such things to him.
"Mm." Bi Han breathes out softly in response, breaking the comfort of the silence. His face finds the crook of your neck, as if he is trying to hide from it, even though he doesn't want to stop. He likes the way you treat him, the words and the damn caresses, and he hates this weakness in himself.