Responses
Chihwan was being poisoned from Soobin’s blood. So it took away his vampire powers, or was turning him mortal. That’s why he couldn’t use his own blood to turn him into a vampire. Chihwan used Seungha’s blood to turn Sooin. Sooin woke up after being turned, saw Chihwan dying and gave him his blood, creating a link. So now Sooin is the vampire and Chihwan is mortal and the link.

Can somebody explain me the end..I'm confused .. I know they are a link now but, Sooin is now a vampire and Chihwan is human?? but how he become human?? x_X