Shin Tsukimi, who's going by the name Sou Hiyori, is a timid job hopper stuck in a death game. He seems to have a worrisome past.

He was abused by the real Sou Hiyori, or Midori. They met in high school but Midori was secretly an adult. He groomed, manipulated, assualted, and hurt Shin, giving him major trust issues. 

Shin is extremely paranoid all the time now. He is cautious and scared, and wants to live. The only thing he wants more than to live is for his sister, Kanna, to be happy. 