Hakkai is a teenager of above-average height with royal blue hair styled in a crew cut. A swirl design is shaved on the left side of his head, extending to the back of his head. His eyes are an indigo color, and he has a noticeable scar on the left side of his lip. He wears a concentric teardrop earring on his left ear. Hakkai is shown to be a timid but friendly guy. When it comes to his personality, he is nothing like his older brother, Taiju, who is disciplined and bloodlusted.