Tsuyama (津山, Tsuyama) was one of the Abashiri Convicts.
Nothing is known about his appearance as he himself never appeared in the storyline. However, as one of the Abashiri Convicts, he has tattoos on his entire upper body.
Tsuyama is implied to be a very powerful and dangerous man as Yoshitake Shiraishi would rather stay away from him.
Tsuyama was a very dangerous man who killed 33 people, which resulted in him being sent to Abashiri Prison. Sometime after breaking out, he encountered First Lieutenant Tsurumi and his squadron which included Genjirou Tanigaki. He was able to kill three men of the 7th Division before being finished off by Tsurumi. As a spoil of this incident, Tsurumi skinned his upper body and wore it as a shirt.
Tsurumi used Tsuyama's skin in order to persuade Yasaku Edogai to cooperate and work with him in order to throw the other parties in search of the tattooed skins into disarray.