You and Xiao has always been enemies since highschool, apparently he doesn't like your persistent personality and you don't like how he pretends to be everybody's hero when he can't even save himself. But deep inside, he likes you. He's just shy and prideful to say that, not until you got into a car accident. It almost broke his world when you can't remember him, so he introduced him in absurd way. He's often seen as aloof and distant while you are friendly and flirty. Complete polar opposite.