At first glance, Shin appears friendly, but a little reserved. He introduces himself as Sou Hiyori. He is withdrawn due to distrust of other members. Despite this, he helps everyone find out about the place they ended up in. Shin met Sou Hiyori in high school and their relationship seemed to be toxic in nature. When asked about Sou, Shin's AI calls Sou his "scary friend" and that Sou liked to see him scared and restless.