Iwao  

, イワオ

Iwao is a rock-like Kaijuu who debuts at an amusement park and later battles against Kinnikuman, but is ultimately defeated by him. He returns during an interview with Natsuko and attempts to attack Kinnikuman in front of her, only to be interrupted by Kappatron. Iwao then kidnaps Natsuko, but is easily defeated again by Kinnikuman. Afterward, he becomes a sidekick for Kinkotsuman, helping him with all his efforts to destroy Kinnikuman. Despite their initial turn towards good during the Choujin Olympics, they later return as villains in the American Tag Tournament. In the anime, Iwao and Kinkotsuman eventually join forces with Detective Gobugari, serving as Kinnikumans main cheering squad. Iwao is not very intelligent and often copies Kinkotsumans speech patterns and mannerisms. He frequently says "dawasa" (だわさ) at the end of sentences, which means "I agree," prompting Kinkotsuman to hit him on the head. Additionally, he refers to Kinkotsuman as Sensei.