|Branch of Sin||Unknown|
|Manga debut||Chapter 12|
|Anime debut||Episode 8|
Kosugi's hair is gray on the top and black at the sides. It is combed backwards. He wears a bartender uniform, a white shirt and a black waistcoat that has a pocket on its left side with a pen in it. He also has a black thin band around both his arms (only his left arm in the anime), as well as a death row collar around his neck.
In the anime, his right arm is a prosthetic, which can be freely removed. Underneath it is a hidden knife.
Scar Chain Arc
Kosugi first appears at the Scar Chain meeting, introducing himself to Ganta Igarashi. When Shiro asks for a snack, Kosugi, being a bartender, professionally makes her a milkshake (ice cream in the anime). After seeing how innocent she seemed, he asks her why she is in Deadman Wonderland, in which she responds that DW has always been her home.
He was present during Nagi Kengamine and Karako Koshio's presentation about the planned breakout. When the prison break began, Kosugi joined the first Scar Chain group in an attempt to escape to the elevator. After coming off the elevator, he and the others were interrupted by the Undertakers as they started to attack them.
As Kosugi fends off the Undertakers, he pulls Ganta aside, telling him he must get the data chip to the surface at any cost. As he hands over the data chip, an Undertaker ambushes them from above. Kosugi takes a sharp metal bar (a hidden knife from his prostate arm in the anime) in attempt to protect Ganta, which ends up him and the Undertaker taking each other out simultaneously. Kosugi, desperately, utters to Ganta that the data chip is their only hope. He dies shortly after.
Hidden knife: In the anime, his right arm is a metal prosthetic, under which he hides a small knife.
In the manga, he uses a sharp metal bar in order to defend Ganta from the Undertaker, simultaneously taking each other out.
Branch of Sin: Kosugi was a Deadman, so he had the ability to freely move his blood out of his body.
His personalized Branch of Sin was never shown.
|G Ward||Kiyomasa Senji · Minatsuki Takami · Chaplin Sukegawa · Idaki Hitara · Itadaki "Masu" Kazuya · Mitsuzaki Yosuga · Toto Sakigami · Albatross · King Fisher|
|Scar Chain||Ganta Igarashi · Nagi Kengamine · Karako Koshio · Rokuro Bundō · Endō · Ohara · Kosugi · Kōmoto · Miya/Harumi · Wakabayashi · Yamazaki · Akiyama · Ueshima · Miyako · Kazu · Fujiyoshi/Matayoshi · Unnamed Deadman|
|Other||Shiro · Wretched Egg · Chan and En · Hagire Rinichirō · Keigo Ugachi (OVA only)|