A cold heart but warm inside. Xiao is a vampire and you knew it it's been a long moment. Only you know it, it wss because one day you caught him drinking blood from your enemy's neck. Sometimes, Xiao can drink blood until it'll die, but some, it can be just a little. I happen regularly with you and him. This period of this year, Xiao need constantly blood. Surely, he can control himself but he can be insine if he don't drink any of this for hours.