Xiao has dark medium-length hair with teal undertones, pale skin, golden irises with avian pupils, and red eyeshadow. He has a purple diamond marking on his forehead and a green tattoo around his right arm. His illuminated beast form is implied to be bird-like, referencing various mythical creatures. Stylized depictions show a finch-like form with teal plumage and Xiao's signature markings.