Regarding the roles of Ide in “Ultraman” and Anne in “Ultraseven,” it is known that the performers originally arranged to appear in the shows were replaced by Masanari Nihei and Yuriko Hishimi.
As to Ide, the character was initially slated to be acted by Susumu Ishikawa (1933-2012) who was a popular actor and singer in those days.
Ishikawa, nicknamed Kewpie-chan (“chan” is a Japanese suffix coming right after someone’s name mainly used for children, girls or someone close to you), was a man who funnily acted Chief Nishioka of New Tokyo Station in Ultra Q Episode 10 featuring M1.
It is said, although the filming started with Ishikawa included for Ide, Ishikawa got out of the show in a few days. And Masanari Nihei who had appeared in “Ultra Q” for three episodes (Episode 2; 6; 15) was chosen for the role of Ide in the end.
While Ishikawa seems to have left the show for reasons related to his own schedule or his appearance fee, it is likely that the scenes that were already filmed with Ishikawa had to be reshot with Nihei.
Ide was portrayed as a man with complex personality as he acted as a comic relief with funny remarks and behaviors and, at the same time, he was so sensitive that he got distressed about Jamyra and protested against attacking the kaiju that used to be a human.
The mistake he made about Pester made him feel so much responsibility in Episode 13, or he was troubled questioning if the SSSP would still be necessary even with the presence of Ultraman in Episode 37.
It is assumed that, if Ide should have been played by Ishikawa instead of Nihei as it was originally arranged, the directors including Akio Jissoji would never have depicted Ide as such a character with a profound personality.
When I was a kid, Ide was definitely an impressive character I was drawn to along with the other main characters, and I think Nihei should be given credit for having helped to make the character that much attractive and impressive far beyond just a comical dude.