Time loop.
He must live to break the cycle bc his blood is the only cure.
oh?
That's what I only knew from others spoiler.
So whenever Hyohyun died the sunbae experience transgression.
**Regression
wonder how hyohyun is connected to the experiments, but thank you ^^
Sooo how is hyohyun connected to the zombie apocalypse? Is it a video game? is youngwon experiencing psychosis? Is it actually happening? Is it some sort of time loop?