Uniformly depicted as a horrible, lecherous doctor, Dr. Iwata owes his prominence in the medical profession mostly to family influence. His most distinct physical feature is the X-shaped scar across his entire face, which was given to him by a four-year old Norikuni Iwata, his cousin, whom he has come to hate since then. His likeness and character are parodies of Osamu Tezuka's Black Jack. Although several chapters of the manga revolve around him or his hospital, he only has cameo appearances in the anime.

(Source: Wikipedia)