Teacher at Sarayashiki Junior High
Mr. Iwamoto (岩本, Iwamoto) is a teacher at Sarayashiki Junior High and is Yusuke Urameshi's enemy.
He is voiced by Minoru Inaba in the Japanese version and by Ed Blaylock in the English dub.
Mr. Iwamoto is a bespectacled man in his 30s with short black hair who wears a green suit with a yellow necktie.
He is a man who claims to strongly care for the reputation of his school, though in actuality, he only seems to care about himself. He is a hypocrite, as he is extremely critical of delinquents and thinks they are the scum of society who deserve to die, yet, when he sees a valuable fountain pen, in attempting to frame Yusuke, he "appropriates" it (steals it); sadly, it led to his own downfall.
When Yusuke died, he viewed this as a positive development as Yusuke's selfless sacrifice would improve the reputation of the school, but agreed with Mr. Akashi that it was more likely that he was chasing after the boy and just happened to get hit by the car.
He seems to like Keiko for her consistently good grades and constantly orders her to stop hanging out with Yusuke, while she mocks him behind his back.
In the anime, it is he who gives Mr. Akashi the idea to intentionally erase Kuwabara's correct answer and replace it with a wrong answer intentionally in an attempt to hurt one of his friends' chances of supporting his family.
He insults Yusuke when he is in person and behind his back as well as tried to frame him for theft after he returned to life, only to be later struck from behind by Yusuke with his newly acquired Spirit Gun. He hit the floor hard. He was unaware that Yusuke hit him. Iwamoto is later possessed by a Makai insect and attacks Keiko but she and Botan give him a taste of his own medicine. Though he eventually corners them, Iwamoto is knocked out once Yusuke destroyed the Makai whistle.
Despite his theft of the student's belongings in an attempt to frame Yusuke, along with his attack upon Principal Takenaka and Keiko while possessed by the Makai insect (which he was grilled by the police while claiming to not remember), he was strangely not fired and continued to be employed as a teacher (possibly under probation), even in the final season. At the end, he failed to expelled Yusuke.
- He often calls Yusuke and Keiko (At Episode 19) "cockroach."
- In the English Dub, Mr Iwamoto provided an accent of Edward G Robinson whose catchphrase is “Yeah, See?".