I am amazed... they didn't rlly considered getting the paternity test with one another within the 5 years???? Oh well, I wanna see how surprised they'll be when they find out they're related 
btw, I don't read the novels and this is basically just my assumption since it's RLLY RLLY obvious and I have read enough manhwas to know what to expect
I am a very bored & stressed highschool student who is being relied on too many group projects bcs of my high participation and grades- I miss the old times where I dnt care abt my grades-