Shiori Imai is a student who only appears in one chapter of Gokusen. She meets Uchi during a festival held at her school, where she held a sort of horror house next to her classmate's cafe. Though terrified after meeting her, Uchi is smitten after seeing her without her makeup on. And she returns the feelings, quickly becoming his girlfriend.
Little is known about Shiori, beyond the obvious factor that she is a big horror fan. It is hinted in a flashback that she had a fondness of pulling pranks on her little brother Haru.
She once told him a ghost hand would appear in the toilet in their bathroom. This gave the child a big fear of using the restroom for the moment.
Shiori is seen as a little weird by her classmates, due for her insane love of horror movies. While her classmates wanted to hold a maid cafe for their festival. Shiori insisted and begged to have a sort of horror house instead. They agreed to let her have one next door to their cafe.
On the day of the festival at their school, Noda, Uchi, and Minami attended. While the other two boys were tricked to go into their expensive cafe. Uchi choose Shiori's haunted house set, mostly because he was broke and Shiori let people come in for free. All her hardwork paid off as Uchi was very afraid from the settings and even more scared when Shiori appeared as a onryō (probably influenced from the Grudge).
Shiori may have overdone it, though, as Uchi quickly passed out from fear. With Noda and Minami gone, Shiori single-handedly carried Uchi to the doctor's after he passed out (twice). When he awoke, Shiori had taken off her make up and was in her normal clothes. Shiori quickly thanked him for before, as she saw his fainting as a compliment that she did a good job on her work.
Though confused by what happened, both the two admit there was an attraction between them. Shiori and Uchi develop a relationship; much to the shock of his classmates. Yankumi and the others followed Uchi to spy on the pair, they would all get a surprise. Shiori would try another horror trick she learned by having a false head fall off.
Uchi instantly passed out, believing her head had fallen off. The others were left stunned and bewildered by Uchi's new girlfriend. But were more shocked that it scared even Yankumi who passed out from Shiori's stunt.
Shiori isn't seen after that. But she is mentioned near the end of the manga. She and Uchi were still together. Uchi may even want to continue their relationship after graduation. As he mentions that he was thinking of becoming a make up artist for movie monsters to stay close with Shiori.