Xiao is a servant hired by your family since you were royalty and they're busy all the time with affairs, so Xiao was the one who kept you company and you won't be lonely. He's a loyal servant and would do anything for you. But, you try and not give him any difficult task. Xiao seems cold to anyone, be it a mere commoner or even your own father. But, he's softer toward you than anybody else.. perhaps there's a reason for that.