Koichi is a character from the sixth episode in the Shigofumi series.
Koichi is regularly bullied at school and vents about it online under the screen name Half-Dead Person. One person in that chat room ends up being a fellow classmate, Shunsuke Morishita. Koichi begs Shunsuke for help but Shunsuke ridicules him and goes as far as setting up for a potentially fatal prank, walking across the a steel beam connecting two buildings. Koichi either dies because of the prank or survives and commits suicide later.
Later in the episode Shunsuke becomes the new victim for the bullies and is forced to do a blindfolded version of the steel beam prank. As the bullies close in on him, Fumika arrives to deliver a shigofumi from Koichi. The letter mocks Shunsuke and Fumika disappears, leaving him to his fate.