Mondo is a tall, muscular boy with fair skin. His natural hair color is dark brown. His face often shows anger.

Mondo's appearance is very typical of Japanese motorcycle gangs. He has an unusual hairstyle and, like all gang members, he dyed it light brown, but there are still small strands of hair that are his natural color.

Mondo's clothes consist of a black coat known in Japan as "tokkō-fuku" (特攻服) decorated with the symbol "The Crazy Diamonds". He wears loose, black trousers held by a belt.