Koichi Shidou is the teacher of Class 3-A from Fujimi High School. He is seen as an egotistical man who plans on ruling the new world with the loyal cult of former students.
Shidou Koichi is the son of a corrupt Tokonosu Prefecture politician. He put on a positive face for the public but privately drove Koishi's mother to suicide. He grew up thinking that his father would have him be his successor, but he was passed over for his half-brother. He became a teacher at Fujimi High School and used what little influence he had to torment the students he was in charge of. When his father became under investigation by the police, Koichi's father called to have him manipulate the grades of that officer's daughter and forcer her to repeat a grade. The investigation when on, but before it could lead to a conviction of both Koichi and his father. There was an outbreak of Them ( zombies) swarming across the world with no sign of stopping. He survived the outbreak with some other members of his Class 3-A in the school.
The character of Koichi Shidou is the main antagonist of the manga/anime series Highschool of the Dead that was written by Daisuke Sato and illustrated by Shouji Sato. The series first began serialization in Fujimi Shobo's Monthly Dragon Age magazine in July 2006.
His first appearance was in Hightschool of the Dead Volume 1 CH. 2 "Escape from the Dead", and his first anime appearance was in Highschool of the Dead - Episode 1 "Spring of the Dead". His appearance in Episode 1 is a brief cameo and has no spoken lines. The first speaking appearance is in Highschool of the Dead - Episode 3 "Democracy Under the Dead". His character in the Japanese series is voiced by Kishou Taniyama, and the U.S. dub produced by Section 23 is done by Illich Guardiola.
Shido Koichi is an egotistical and menaical, using the power of manipulation to make himself appear like a God of sorts to the other students, who blindly follow. Comparable to Hitler or Charles Manson, Shido's motives appear almost cult like as his words make him out to be the new God of the world after the outbreak. He is shown to be a coward though, recoiling after Kohta's attack and fearing the zombie infestation at the high school.
His group of survivors running towards the bus Takashi and others were on. Rei sees him and immediately beckons that Shizuka drives off without him, claiming that it would be the biggest mistake to rescue him. Takashi does not understand what the big deal is as we see Shido pushing children to get to the bus before him until one final student trips and sprains his ankle. Shido, believing in a bastardized version of Survival of the Fittest, kicks the student in the face, causing his glasses to shatter, blinding him and leaving him to die in a group of zombies before the teacher runs to the bus. This event is not mentioned by any of the other survivors on the bus, which can only mean that none of them saw what happened.
As Shizuka drives off from Fujimi High, one of the other male survivors starts to butt heads with Takashi, claiming to hate him before being pummeled by Rei. Shido claps sarcastically and states that the group is unorganized and thus needs a leader to take it over. Giving a speech about leadership and loyalty, the four students who came in last applaud his work while the original survivors scorn his words. Rei, fed up and with the bus stopped, gets off with Takashi following in pursuit. After a bus crash blocks the two off from the rest of the group, Shizuka drives to the rendezvous point Takashi and Saeko established.
However, Shido uses it as an example to claim that his leadership is above all else, winning the favor of two younger female students by embracing them when they get scared, giving another speech as his face has a perverted look to it. After being stuck in a traffic jam do to bridges being blocked off, the original group of survivors band together to claim Shido as an idiot, Kohta getting the most aggressive as he fires his nailgun as Shido, scarring him as Kohta explains that Shido allowed him to get bullied as he watched on with glee. At this point, Shizuka, Saeko, Takagi, and Kohta get off the bus, leaving Shido with his new followers.