No it's not.
Just because KS it's the only horror/thriller you know doesn't make every other thriller be similar to it. One is a stalker who's in love with a psycho and breaks to his house, ends up kidnapped and participates in his crimes due to love and stockholm syndrome. The other is an renomed Author who's a serial killer and likes playing twisted games and manipulating people.
I mean, they are blonde and a brunnet, is that it? Their generic haircolors that you find in any other work?
Holly shit, I was so rude.
My apologies, I shouldn't have done that. ╥﹏╥
no not at all the only similarities is that the killer is blonde and the victims has black hair
GUYS ITS SIMILAR TO SANGWOO AND A YOONBUM STORYY