Hiroo appears to be somewhat lethargic other than his teammates. He also doesn't talk very much, but when he does, it's often to taunt his opponents across the net in a volleyball game, or anyone in general. Hiroo has straight, medium-length black hair with short bangs that hangs over his left eye. His eyes are black and slightly large. He's usually seen with a stoic, or even a bit tired facial expression. He's also a pretty good player with a powerful serve and a great middle blocker.