Haku appears to be around 12 years old in physical age. He has straight, dark green hair in a bob haircut and slanted, green eyes. When he is human, Haku wears a traditional white robe that resembles closely a Kariginu tied with a lavender sash, a short traditional indigo dyed Sashinuki (a type of kuribakama) underneath, and beige sandals. A darker blue Hitoe can be seen from the sides and shoulders of the robes. When he transforms into his dragon form, he has a teal and mint green mane, with a white, scaled body.