柊乃 蒼佑

The SHEEPIII's underwater voyage doctor. An unkempt but brave individual, willing to put his life on the line to do his duty. He is ready to do what needs to be done and is by no means irresolute. Nevertheless, he is susceptible to pressure. As a doctor, he values lives and makes efforts to save all of them, though he understands perfectly well that it is not always possible.

Sousuke was picked for the particular underwater expedition because of his remarkable medical skills. Little did he know, to which nightmare this assignment would lead...

In truth, prior to the "Fourth Day" incident, he brought a very dear person to him in an oceanarium. On the way back, a supernova explosion of Betelgeuse occurred, which led to a massive traffic incident. It entangled Sousuke and that person as well. The first one was almost intact, while the second one was dying. Sousuke then began to help with the triage of the injured. He assigned his dear person a red tag, despite her condition requiring a black one. That person was saved at the cost of other lives. It has since become his trauma.