Responses
Blonde is obsessed with Jin because Jin did something to him that blonde wants revenge for. Something along the lines of "Jin bullied the blonde" and now the blond coughs up blood and is wired up to a IV machine. It must be pretty bad since Jin did it when they were in daycare and it's still affecting blond through his adult years. Blond hasn't physically recovered and probably emotionally as well which has lead to him wanting revenge... But the author has also drawn up a relationship chart that showed blond likes Jin. So blondes obsession could be something mixed between Revenge and Romantic Interest.
I don't get the plot but why this gotta be a doomed yaoi . Why is the blonde guy from security obsessed with Jin?? Anyway all of them got a couple so good . I think the snake guy will create a cyborg outta charin and lives happily with him or smth . And Jin with this black haired?