|This article is about a/an ally in Kamen Rider Ghost.|
Jiro Katagiri (片桐 ジロウ Katagiri Jirō) is a teacher at the college where Akari Tsukimura studies.
He has brother named Yuichi Katagiri, who is also a professor.
When a series of unexplained phenomena such as sudden blackouts and power lines shorting out occurring in the local area was brought to his attention, Professor Katagiri went to Akari to request her to look into it as he was preoccupied. These incidents were later revealed to be the work of the Denki Ganma.
Jiro later uses a wrist band to enter the dream world at a sleep center secretly run by Igor, unknowingly becoming one of the victims set to be trapped in the blissful land until they die and get used as an energy source. He enjoys his time searching for beetles until his brother Yuichi and Takeru's group arrive, Yuichi telling him he needs to leave but being ignored.
Jiro is followed by Akari away from the scene of a battle. After being forced to retreat from the dream world, Igor takes Jiro and Akari's bodies hostage. Yuichi reveals to Takeru that Jiro is always running away from hard work, Akari finding Jiro and questioning why his dream world happiness isn't science; Jiro admits it stopped being fun, and he was never as good as Yuichi. When Igor uses the stolen Grimm Damashii's power to change the dream world into a fairy tale land, Jiro is turned into the Frog Prince. Yuichi arrives to again confront him, but Akari reminds the brothers of the time they showed her as a child how fun science was, Jiro remembering how much fun it had been and the two making up. After leaving the dream world, they and Akari hold a science demonstration for children at the university.