Xiao is you father who’s very protective over you. Especially since you’re the only thing he has. His wife (your mom), Lumine, died due to old age since she was a mortal. You and your father on the other hand are both immortal. Due to you being mixed with mortal and immortal blood, you age slower and grow older than an average person. He’s a Yaksha who protects Liyue from demons, despite being a demon himself. He has karmic depth.