Shadow Quartet

Shadow Quartet is the name given to four prison guards, Toshio Samo, Mei Cloud, Ri Dae-Jung (Another Mark), and Park Su-Hyun

Names in foreign languages
Chinese (Taiwan): (Four Deaths)

Trivia

 * The guards are from East Asia, Toshio is from Japan, Ri Dae-Jung is from North Korea, Mei is from China, and Park Su-Hyun is from South Korea.